Clinical improvement, toxicity and future prospects of β-sitosterol: a review

ABSTRACT

β-sitosterol is waxy substance, white in color distributed in a variety of natural plant sources cereals, pulses, legumes, vegetables, fruits, and herbs. Several clinical and preclinical investigations indicate that β-sitosterol has a wide range of important health advantages. It prevents many types of malignancies, lowers levels of low density lipoprotein (LDL), lowers the risk of coronary artery disease, heart attacks, and atherosclerosis, and supports the body’s natural healing process. It is found to have cancer-protective properties and has the potency to be beneficial against breast, prostate, colon, lung, stomach, and leukemia. The present review provides a complete analysis and examines the literature on β-sitosterol from different dietary sources, with a focus on its toxicological characteristics and nutraceutical qualities. It lays down the theoretical basis and justification for directing the future planning and execution of clinical studies intended to confirm the importance and possible toxicity of β-sitosterol.

KEYWORDS:

• Phytosterols
• stanol esters
• deoxyxylulose and mevalonate pathway
• low density lipoprotein (LDL)
• coronary artery disease

1. Introduction

Numerous compounds that are not only nutrients but can also prevent disease are found in plants. “Phytochemicals” refers to the principal compounds that plants make through their primary and secondary metabolism (Ferahtia, 2021). Its name, phyton, is a Greek word that means “plant.” More than a thousand different phytochemicals are produced by plants for a variety of reasons, including growth and defense against diseases and rival plants. The word “Phytochemicals” was first used in 1994, and soon after, scientists and researchers started to take an interest in it. Phytosterols, a subtype of steroids, are one of the significant types of bioorganic compounds (Ferahtia, 2021). The form of phytosterol β-sitosterol (plant sterol) that is most prevalent can be found in a variety of plant-based foods, including natural oils, soy products, including nuts. Numerous studies have shown that sitosterol has therapeutic and clinical uses that include decreasing cholesterol and low-density lipoprotein levels, neutralizing free radicals in the body, and, most intriguing, curing and preventing cancer (Afzal et al., 2022). Alginate/Chitosan nanoparticles with encapsulated -sitosterol (β-sitosterol Alg/Ch/NPs) are being tested for their efficacy in treating breast cancer as well as their in vivo pharmacokinetic characteristics (Afzal et al., 2022). Compared to other cancers, breast cancer affects women at a higher rate than the others (Zaheed et al., 2020). According to current projections, in situ diagnosis of ductal carcinoma as well as melanoma in the female breast were 49,290 and 101,280, respectively, in 2021 (Siegel et al., 2021). Sterols, which are regarded as membrane reinforcers because they preserve the domain structure of cell membranes along with control crucial biological processes, is the third most significant class of lipids (Yin et al., 2018). The primary sterol in vertebrates is cholesterol, which is mostly located in animal cell membranes. It functions as a secondary messenger in developmental signaling and has an impact on the fluidity of the cell membrane (Akihisa et al., 1991). Through a chick embryo chorioallantoic membrane assay, the angiogenic component (β-sitosterol) was isolated from the Aloe-Vera gel, and its impact on damaged blood vessels of the Mongolian gerbil was examined. It was discovered that intraperitoneal administration of β-sitosterol significantly improves the formation or motion recovery of new vessels in gerbil brains damaged (Choi et al., 2003). One of the most prevalent phytosterols found in human diets, β-sitosterol is present in high concentrations in the nonpolar portions of plants as well as marine organisms (200–400 mg daily). Consuming β-sitosterol alongside vitamins or plants that may drop blood sugar levels should be done with caution, as well as doses may need to be modified (Ferahtia, 2021).

2. Methodology

In our methodology, we gathered literature on β-Sitosterol from various sources, including Science Direct, Google Scholar, Web of Science, and PubMed. For access to paid articles, we collaborated with the The University of Lahore, Lahore, Pakistan, which graciously provided free access. We initially created an outline to establish a coherent structure for the review and then conceptualized the content. Adhering to this framework, we structured the review into sections, delving into the overall sources of β-Sitosterol, its bioactive potential in functional foods, and its capacity to combat chronic diseases.

3. Different sources of β-sitosterol

Among 200 plant sterols distributed in plants (Lagarda et al., 2006), β-sitosterol is major (comprising 60% of phytosterols) followed by campesterol (24%), stigmasterol (7%), and minor contents of 5-avenasterol, brassicasterol, beta-sitostanol, and campestanol (Chung et al., 2013). Due to significant health benefits associated with β-sitosterol, these biomolecules need to be provided through diet as the human body is incapable of generating these biomolecules (Chanioti et al., 2021). According to EFSA, 2009, the daily consumption of 1.5 to 2.4 g/kg of phytosterols can reduce the level of low-density lipoproteins in blood on average by 7 to 10.5%.

β-sitosterol is a waxy substance, white in color (Kakade & Magdum, 2012), distributed in a variety of natural plant sources cereals, pulses, legumes, vegetables, fruits (Piironen et al., 2002) and herbs (Gahlaut et al., 2013). Phytoecdysteroid is a crucial chemical for plant well-being and is derived from β-sitosterol which is distributed in various plant tissues like leaves, fruits, and rhizomes (Bin Sayeed et al., 2016). β-sitosterol along with γ-oryzanol acts as a structuring agent in plant oils and their amount influences the different mechanical properties of these oils (Calligaris et al., 2020). Moreover, β-sitosterol influences the metabolism of major bio-molecules and acts as a growth regulator when exposed to strident environmental conditions (Z. Li et al., 2019).

β-sitosterol is been extracted by using technologies like supercritical fluid extraction (SFE) (Sajfrtova et al., 2010), and also by conventional methods of solvent extraction and various chromatographic techniques (J. C. Ye et al., 2010).

3.1. Cereals, legumes, pulses and nuts

Cereals are valuable naturally available plant sterol sources and their contents remain the same for cultivars grown in the same area at the same time, but growing conditions affect sterol content, and various milling products of these cereals also give varied yields (Piironen et al., 2002). This is supported by a study that states, there is an inverse relation between β-sitosterol and total plant sterols in soya beans at elevated temperatures; there is an increase in plant sterol contents by 2.5-fold at the expense of decreasing β-sitosterol (Vlahakis & Hazebroek, 2000). Plant sterol is present either freely or linked through an ester or glycosidic linkage in plants (Hakala et al., 2002). Linked state sterols called “conjugates” could be either esterified to fatty acid or hydroxycinnamic acid or glycosylated with any hexose moiety or 6-fatty acyl-hexose (Moreau et al., 2002).

β-sitosterol constitute a major portion of plant sterols, and these are non saponifiable lipids (Abidi, 2001). Plant sterol contents of individual cereal varieties have been determined by researchers, but there is slight variation in data collected which may be attributed to sample differences, growing conditions, or different analytical methods (Piironen et al., 2002). Total sterol contents in cereals like barley, rye, wheat, rice, and oats are in the range of 0.35–1.20 g/kg, while in crude soya beans, they are 3.0–4.4 g/kg (Chanioti et al., 2021). Specific vegetable oils such as wheat germ and corn germ oil possess good phytosterol contents (Chanioti et al., 2021). Legumes and some seed oils (peanuts, soybean, olives & flaxseeds) contain the highest β-sitosterol contents among plants, which gives these oils stability due to their antioxidant nature; especially in olive oil (Lima & Block, 2019).

Due to stability and appealing flavor, vegetable oil; soybean, wheat germ oil, and rice bran oil (RBO) is employed as salad dressings and frying medium (De Deckere & Korver, 1996). Rice bran, a milling by-product consisting of pericarp, aleurone, and sub aleurone, is rich in bioactive compounds (Friedman, 2013). Certain vegetable oils, especially soya bean are employed for suppression of carcinogenesis (Kakade & Magdum, 2012).

Among nuts highest β-sitosterol contents are found in pistachio (Vecka et al., 2019). They are synthesized from acetyl co-A, and stabilize the phospholipid bilayer in nuts due to similarity in structure with cholesterol (Hartmann, 1998). Extraction and purifying methods could be the reason for reduced phytosterol contents in end products (Gecgel & Demirci, 2006). The following Table 1 elaborates the different sources of β-sitosterol.

Table 1. Different sources of β-sitosterol.

Sources	Extraction method	Compounds extracted	References
Wheat Barley, rye Rice grain	GC-MS (gas chromatography with spectrophotometer	Campesterol, stigmasterol, sitosterol, sitostanol, Δ5-avenasterol	Piironen et al. (2002)
Rice bran, Soya bean, Flaxseeds (oil samples)	Saponification followed by GC/MS analysis of plant sterols	All major plant sterols present with β-sitosterol highest, (ergosterol not detected in flaxseeds)	Yang et al. (2019)
Olive oil	Gas chromatography	Rich in α, β, γ-tocopherols, β-sitosterol, D5-avenasterol, & oleic acid	Lima and Block (2019)
Pumpkin seeds	Acid hydrolysis & lipid extraction followed by alkaline saponification and HPLC analysis	Major compounds extracted were β-sitosterol, stigmasterol & squalene	Ryan et al. (2007)
Fruits
Oranges, peach, tangerines	GLC (gas liquid chromatography)	All (β-sitosterol, campesterol, stigmasterol, β-sitostanol) present except campestanol	Jun-Hua et al. (2008)
Apple and pear leaves	Saponification and GC/MS analysis of leaves extract, HPLC analysis of β-sitosterol	Phytols, squalene and β-sitosterol present in both apple and pear leaves	Hammam et al. (2023)

3.2. Fruits

Fruits are a valuable phytosterol source. The yield of β-sitosterol in fruits relative to total phytosterols is 72–92% (Piironen et al., 2002). Avocado (Persea americana) is a pebbly dark-skinned fruit grown as a major crop in America and is the highest source of β-sitosterol among fruits (Duester, 2001). Individual fruit parts (peel, leaves & seeds) are rich sources of β-sitosterol; seeds of various fruits yield almost 11.8–28.5% plant sterols (Gornas et al., 2016).

Malus domestica Borkh. (Apple) is a widely cultivated fruit in the world. According to FAOSTAT globally 86 million tons of apples are produced. Apple leaves were recently discovered to be a great source of β-sitosterol. 1 gram of dried apple leaves contains 5 mg of β-sitosterol, similarly, pear (Pyrus communis) has about 9.4 mg of β-sitosterol per gram of dried leaves (Hammam et al., 2023).

β-sitosterol extracted from apple & pear leaves, through high-performance liquid chromatography, has shown good wound healing properties when applied in the form of rich emulgels (Hammam et al., 2023). Moreover, phenolic compounds in apple leaves are renowned for their antioxidative properties (Liaudanskas et al., 2014).

3.3. Herbs/Shrubs

Berberis is a genus of plants, belonging to the Berberidaceae family which is characterized by spiny, woody, perennial herbs and shrubs, its Species like jaeschkeana, aristate, lyceum Royle and vulgaris of the genus Berberis are well known as a rich source of vital medicinal compounds (Perveen & Qaiser, 2010). The stem, bark, root, root bark, leaves, and flowers of these plants are rich sources of phytochemicals and phytosterols (I. Khan et al., 2016).

The Fractional composition of sterols in barberry’s (Berberis vulgaris) fruit powder showed the highest β-sitosterol contents alongside campesterol and delta 5-avenasterol (Dubtsova et al., 2021). Berberis aristata is used to extract phytochemicals (caffeic acid, quercetin & chlorogenic acid) & root contents of this shrub have the potential to reduce oxidative stress (Singh & Kakkar, 2009). β-sitosterol, a secondary metabolite of B.aristata provides effective protection from lipid peroxidation triggered by FeCl2 (C. R. Zhang et al., 2013).

The use of Berberis lycium Royle to treat rheumatism, ENT, gastric and skin problem is well known, but recently its root bark has been used to extract β-sitosterol, which possess a considerable cytotoxic potential (Anwar et al., 2020).

Alamzeb et al. (2013) reported that some alkaloid and non-alkaloid fractions obtained from Berberis jaeschkeana also had β-sitosterol which is used as an effective antimicrobial agent.

4. Clinical importance of β-sitosterol

Phytochemicals have long been attracting the interest of researchers due to the countless benefits they offer to human health. Steroids have many subclasses, one such subclass is phytosteroids, which have a structure similar to cholesterol. One of the phytosterols is β-sitosterol. β-sitosterol, which is a plant-derived nutrient, is known to have many health benefits. Much research has been done on this nutrient to study the therapeutic effects β-sitosterol has on the human body. It is found to have cancer-protective properties and has the potency to be beneficial against breast, prostate, colon, lung, stomach, and leukemia. Several studies have been conducted showing the interference of β-sitosterol on numerous cell signaling pathways suggesting its anticancer, anti-inflammatory, hepato-protective, anti-tumor, antioxidant, anti-diabetic, and cardio-protective role, without causing toxicity. β-sitosterol is found in lipid-rich food products such as nuts, legumes, seeds, and extra-virgin olive oil. Owing to the advantages offered by this nutrient, many products that contain β-sitosterol have been commercialized.

Studies have found that consuming low amounts of β-sitosterol may help in cancer by killing cancer cells, therefore decreasing the chances of cancer progression. This cholesterol-like compound is used by humans as a nutrient in amounts ranging from 200 to 400 mg per day. According to the research conducted, this nutrient stops the absorption of cholesterol, hence being beneficial in controlling morbid diseases such as strokes, diabetes, cardiovascular disorders, and obesity. Apart from being a natural chemical that stops the proliferation, angiogenesis, invasion, and metastasis in cancer cells, this nutrient is also known to possess trypanocide and mosquito larvicidal properties (Z. Khan et al., 2022). β-sitosterol helps combat diseases such as coronary artery disease, heart attack, and atherosclerosis by reducing the levels of low density lipoprotein LDL in the body, by helping the body’s recovery process in fighting against morbid diseases. Heavily incorporated in oils such as olive oil, sesame seed oil, flaxseed, canola, and corn oil, this phytosterol has pharmacological and therapeutic benefits (E. Gupta, 2020).

β-sitosterol is known to possess anti-nociceptive activity, a study that was done on mice, in which the mice were given different concentrations of β-sitosterol, suggested that β-sitosterol in concentrations of 5, 10, and 20 mg/kg has anti-nociceptive properties in mice, which was confirmed by tail flick and hot-plate test in mice (Sakul & Okur, 2021). β-sitosterol has positive effects on the colon. In a study that was conducted on mice colon, β-sitosterol was responsible for reducing the colon length and inflammation by reducing the survival chances of Salmonella typhimurium which is known to produce inflammatory responses in the colon (Ding et al., 2019). β-sitosterol was linked to balancing sex hormones in PCOS-like mice and had a positive impact on the gut microbiome at the same time. Therefore, leading to the conclusion that β-sitosterol has beneficial applications in the treatment of PCOS (Yu et al., 2021). In another study conducted on a mice model, it was observed that β-sitosterol had a positive effect on aged mice suffering from Alzheimer’s disease, not only was it found to be beneficial for reducing the progression of Alzheimer’s disease but also had beneficial effects in later stages of Alzheimer’s disease (J. Y. Ye et al., 2020). Table 2 illustrate the sources, disease prevention and importance of β-sitosterol.

Table 2. The sources, study level, disease prevention and importance of β-sitosterol.

Sources	Product	Invivo/invitro study	Disease	Major finding	Reference
Nuts, seed, legumes and olive	Oil	In-vitro and in-vivo	Analgesic, immunomodulatory, antimicrobial, anticancer, anti – inflammatory, hepatoprotective, respiratory diseases and anti-diabetic activities	The major finding of experimental studies showed that the potential phytosterol can be used as supplements to fight against chronic diseases	Babu and Jayaraman (2020)
Plant	–	–	Cardiovascular protection, inhibits tumor growth and modulates immune response	The finding showed that β-sitosterol could be a potential chemo preventive against of various types of cancers	Patel et al. (2017)
Vegetable	Diet	–	Cardioprotective	The results extend existing data regarding the cardioprotective effect of β-sitosterol and provides new insights into understanding the molecular mechanism underlying the beneficial effect of β-sitosterol on endothelial function.	Loizou et al. (2010)
Tall oil	Powder	In vitro	Cancer treatment	The results found that hytosterols (PS) as func-tional ingredients in the development of PS-enriched foods could exert a potential preventiveeffect against human breast, colon and cervical cancer	Alvarez-Sala et al. (2019)
Tablet	β-sitosterol self-emulsion	In vivo	Hyperlipidemia	The finding verified that β-sitosterol self-microemulsion can lower blood lipid.	Yuan et al. (2019)
Crystalline β-sitosterol	Oleogels	–	Cholesterol-lowering properties	β-sitosterol based oleogels are a good replacement of oils. It can be used as a fat replacer and have cholesterol lowering properties.	J. Li et al. (2021)
Plant	–	–	Anticancer, hepatoprotective, antioxidant, cardioprotective, and antidiabetic	Different studies showed that β-sitosterol interferes with multiple cell signaling pathways	Z. Khan et al. (2022)
Plant	–	In vivo and In vitro	Alzheimer’s Disease	The results showed that beta-sitosterol can lessen plaque burden and also enhance spatial learning in patients suffering from Alzheimer’s Disease.	Mishra et al. (2024)
Plant	–	In vivo	Ischemic stroke	The results verified that β-sitosterol may help treat ischemic stroke by inhibiting neuronal intracellular cholesterol overload/endoplasmic reticulum stress/apoptosis signaling pathways.	Tang et al. (2024)
Plant	–	In vivo	Diabetic ulcer wounds	The findings evaluated that the healing effects of β-sitosterol on diabetic ulcer wounds in rats.	Liu et al. (2024)
Plant and animal	Superfood	–	Cancer	The major findings of this review provide future investigations and highlights the need for further research on β-sitosterol as a potent superfood in combating cancer.	Nandi et al. (2023)
Vegetable oils and nuts	Oil	–	Cancers	β-Sitosterol shows promising potential as a therapeutic candidate for inhibiting HCC growth and metastasis through FOXM1 downregulation and Wnt/β-catenin signalling inhibition.	Y. Chen et al. (2024)
Plant	–	In vivo	Inflammatory diseases	The results showed that β-sitosterol may be useful for the treatment of various inflammatory diseases.	P. Zhang et al. (2023)

Not only does β-sitosterol have neuro-protective but it also has anti-diabetic properties. In a study conducted on diabetic rats, it was seen that β-sitosterol balanced the levels of blood glucose, serum insulin, testosterone, oxidative stress markers, and lipid profile all the while improving glycemic control suggesting its positive impact as an anti-diabetic agent (Ponnulakshmi et al., 2019). According to a study conducted on rats in 2020, which focused on the anti-oxidative properties of β-sitosterol with chronic alcohol intake. It was observed that β-sitosterol is linked with reducing oxidative stress caused by excessive alcohol intake. Alcohol-induced liver damage was reduced with the consumption of β-sitosterol in rats. Different concentrations of β-sitosterol had beneficial effects on biochemical indicators that are produced due to the intake of alcohol. The oxidative stress that is produced after the intake of alcohol was significantly reduced in rats such as erythrocyte membrane fluidity was improved, glutathione depletion was reduced and antioxidant enzyme activity was restored (Z. Chen et al., 2020). Due to the inflammation-reducing response created by β-sitosterol, it has promising effects on renal tissues as well. Reducing inflammation, and oxidative stress is the main mechanism by which β-sitosterol reduces renal and cardiac necrosis (Koc et al., 2021). β-sitosterol, which has a structural similarity with cholesterol, is such a nutrient that can be incorporated into food products and can be used in supplements to get the numerous health benefits it offers to humans. Figure 1 illustrates the effect of β-sitosterol on regulation of lipid metabolism.

Figure 1. Effect of β-sitosterol on regulation of lipid metabolism.

4.1. Anticancer

Nowadays, there is a great deal of attention on using everyday lifestyle behaviors to avoid primary cancer. It is well established that β-sitosterol and cholesterol cause apoptosis by inducing caspase-3 activation in cells. Although they are not as readily absorbed as cholesterol, plant sterols nevertheless have an effect on a number of physiological functions. These substances effectively lower blood levels of low-density lipoproteins and minimize the risk of atherosclerosis. Furthermore, they reduce the viability of both cancer and normal cells in a way that depends on exposure time and dosage (Rubis et al., 2008). Regular consumption of liposomal β-sitosterol on a daily basis may prevent tumor metastasis by potentially boosting the effectiveness of gut immune surveillance mechanisms (Imanaka et al., 2008).

4.1.1. Colon cancer

The proliferation of COLO 320 DM cells is inhibited dose-dependently by β-sitosterol (IC50 266.2 microM), which also scavenges reactive oxygen species to cause apoptosis and suppresses the expression of β-catenin and proliferating cell nuclear antigen in human colon cancer cells (Baskar et al., 2010).

Adding β-sitosterol to colon cancer cell lines prevents them from growing without changing the overall amount of phospholipids in the membrane. It is most likely the effect on signal transduction pathways connected to membrane phospholipids that is responsible for this growth inhibition (Gu et al., 2023).

4.1.2. Breast cancer

β-sitosterol inhibits the invasion of tumor cells, such as MDA-MB-231, through Matrigel and their adhesion to plates coated with collagen I, collagen IV, fibronectin, and laminin, consequently restricting the adhesive interactions between tumor cells and the basement membrane. Exposure to β-sitosterol leads to its accumulation in the membranes of transformed cells (Awad et al., 2007). Apoptosis induction, which is accomplished by inhibiting the extracellular signal-regulated kinase 1 and 2 (ERK1/2) signaling pathway, causes cell death. Increases in proapoptotic Bcl-2 protein levels and decreases in procaspase-9 and procaspase-3 levels are involved in this process. Notably, after treatment, these impacts on normal cell controls are negligible, keeping cell viability levels at ≥ 80% (Tasyriq et al., 2012).

4.1.3. Prostate cancer

When human prostate cancer (PC-3) cells are supplemented with β-sitosterol, their proliferation is suppressed, resulting in cell cycle arrest in the G2/M phase. In addition, it promotes prostaglandin secretion, raises ROS levels, and triggers apoptosis. Furthermore, it prevents PC-3 cells from encroaching on Matrigel-coated membranes and from attaching to fibronectin and laminin, which may indicate that growth and metastasis are inhibited (Reddy et al., 2022). In vitro primary prostate stromal cell cultures supplemented with β-sitosterol express and secrete transforming growth factor β1 (TGF-β1) and Protein Kinase C-α (PKC-α), which translocates to the cytosol from its membrane-associated active form (Dedić et al., 2023).

4.2. Antidiabetic

When diabetic rats induced with streptozotocin received oral doses of β-sitosterol at 10, 15, or 20 mg/kg for 21 days, there was a reduction in glycated hemoglobin, nitric oxide, and serum glucose levels. Simultaneously, there was an increase in antioxidants and serum insulin within pancreatic cells, alongside a decrease in thiobarbituric acid-reactive substances (R. Gupta et al., 2011). In a study, oral SIT treatment reduced fasting blood glucose and enhanced oral glucose tolerance in hyperglycemic rats by raising fasting plasma insulin levels; the outcomes were contrasted with those of the conventional medication Glibenclamide (Babu et al., 2020).

4.3. Antihyperlipidemic activity

β-sitosterol disrupts the absorption of micellar cholesterol, resulting in reduced influx of plasma membrane cholesterol and secretion of cholesteryl ester (Mel’nikov et al., 2004). β-sitosterol reduces the synthesis of cholesterol by affecting the expression of the HMG-CoA reductase gene (Liang et al., 2015).

4.4. Immunomodulatory disorders

By inhibiting eosinophil infiltration and goblet hyperplasia-induced mucus hypersecretion, β-sitosterol reduces the generation of reactive oxygen species. In lung tissue and bronchoalveolar lavage fluid, respectively, lactose-β-sitosterol and β-sitosterol block elevated mRNA and protein production of IL-4 and IL-5. One of lactose-β-sitosterol’s (L-BS) anti-asthmatic properties is demonstrated by its ability to obstruct IgE in bronchoalveolar lavage fluid and to reduce mouse splenocyte survival rates (Yuk et al., 2007). When activated via the conventional pathway, glucoside-3′-O-β-sitosterol has been demonstrated to exhibit a strong inhibitory effect on the complement system (Ambavade et al., 2014).

4.5. Neurological disorders

Dietary β-sitosterol is able to enter the brain and build up in the brain cells’ plasma membrane. β-sitosterol in the mitochondrial membrane enhances the fluidity of the inner mitochondrial membrane while leaving the fluidity of the outer mitochondrial membrane unaffected. As a result, this increase in mitochondrial membrane potential (∆Ψm) and mitochondrial ATP content could potentially offer benefits for neurodegenerative disorders such as Alzheimer’s disease (AD) (Shi et al., 2013). This incorporation effectively shields against oxidative stress and lipid peroxidation induced by glucose oxidase. Moreover, it enhances PI3K activity, facilitates the recruitment of PI3K to lipid rafts, and promotes the expression of p-GSK3B. Notably, these effects can be counteracted by estrogen receptor antagonists. Hence, nutrients enriched with β-sitosterol hold promise for ameliorating neurodegenerative disorders such as Alzheimer’s disease (AD) (Sharma et al., 2021).

4.6. Reproductive issues

Brown American mink (Neovison vison) were given 50 mg/kg/day of β-sitosterol for 10 months, and this improved reproductive success suggests that β-sitosterol might be employed to improve these mammals’ reproductive capabilities (Balkrishna et al., 2021). Plant sterols, predominantly β-sitosterol, elevate testosterone levels in the testes of male pups in the F2 generation, raise plasma testosterone levels, and reduce relative uterine weights in F2 and F4 generation pups. Additionally, they boost plasma estradiol concentrations in female pups of the F3 generation. Despite these temporary alterations, there are no lasting detrimental effects on mouse reproduction (Kopylov et al., 2021). Figure 2 elaborates the therapeutic potential of β-sitosterol in detail.

Figure 2. Therapeutic potential of β-sitosterol.

5. Toxicity

The phytosterol, β-sitosterol is known for its benign uses, but there is a limit to its consumption for humans. Even a beneficial compound can have detrimental effects if it is misused. β-sitosterol may have many health benefits, but a limit is set up for its usage daily to avoid toxic buildup in the body. β-sitosterol has many pharmacological uses such as antibacterial, antinociceptive, stabilizing activity, thrombolytic activity, anthelmintic activity, antibiotic activity, anti-diarrheal, and hepato-protective activity but only within a certain range, it is thought to provide these benefits (Kudumula et al., 2021). However, the control for supplements is not as strict as it is for drugs. Anyhow, The US Food and Drug Administration has set up daily limits for supplements and drugs to avoid the overconsumption of these substances. β-sitosterol is consumed as a supplement in many forms; it is either incorporated into food items or is taken as a dietary supplement. Various companies have mixed β-sitosterol in margarine, yogurt, and other foods. The daily consumption of β-sitosterol incorporated into food 1.5 to 3 grams per day. Whereas, to reduce the levels of low density lipoprotein LDL in the body by 6% to 15% it is estimated that the body requires almost 2 grams of β-sitosterol per day. For the treatment of a swollen prostate, the limit ranges from about 130 mg to 180 mg per day. It is noteworthy that the intake of β-sitosterol can lead to reduced levels of vitamin E and carotene so, supplementation of this vitamin should be considered along with using β-sitosterol. This is the limit for the consumption of β-sitosterol daily if the limit is exceeded, there can be dire consequences. People who have already had a heart attack were observed to have increased chances of other heart-related diseases. Phytosterols are generally regarded as safe GRAS, but these sterols should be consumed within safe limits as they can trigger an underlying condition. It has been observed that β-sitosterol has been linked to causing many gastrointestinal disturbances such as flatulence, stool discoloration, changes in appetite, dyspepsia, leg cramps, skin rashes, leucopenia, and in a few cases can also cause impotency. In a study that was conducted on rats, it was seen that at higher doses of 5 mg/kg, the rats became infertile. With increased therapy, a decrease in the testicular size and sperm count was observed whereas, a one-year trial in which patients were given 1.6 mg of dosage daily, showed an overall reduction in the cholesterol (Matsuoka, 2022).

6. Limitations and enhancements of β-sitosterol

When exposed to 180°C for two hours, 75% of cholesterol and β-sitosterol oxidized, demonstrating their thermal instability. β-sitosterol’s oxidative behavior was similar to that of cholesterol in terms of both the rate of oxidation and the compounds that were produced as a result (Xu et al., 2009). The application of β-sitosterol is related to its poor targeted efficacy and absorption (Wang et al., 2023). β-Sitosterol (SIT) has a low intestinal absorption capacity and a high rate of biliary excretion, which reduces its bioavailability concentration (Gil-Ramirez et al., 2014). Large dosages of β-sitosterol (up to 25 to 50 g/day) are required to achieve a desired drop in serum cholesterol levels (Marangoni & Poli, 2010).

The butylated hydroxyl toluene BHT, green tea catechins, alpha-tocopherol, and quercetin were more effective at preventing the oxidation of beta-sitosterol and can improve the thermal instability (Arivarasu, 2023). By adding SIT to PLGA nanoparticles, its concentration-dependent antiproliferative effects on MCF-7 and MDA-MB-231 cells were enhanced compared to conventional carrier vehicles (Andima et al., 2018). β-sitosterol (SIT) has been created into nanoparticle formulations to overcome its problems relating to low targeting efficacy, poor aqueous solubility, and systemic bioavailability. The usefulness of these SIT-based nanoformulations against cancer has been studied, and the results show a much more promising efficacy (Karim et al., 2022).

7. Future prospects of β-sitosterol

β-sitosterol has great potential considering the anti-cancer effect it has on the body. But, currently, the research has slowed down a bit on β-sitosterol. Whereas, if efforts are made in the research industry this plant sterol can do wonders. The only limiting factors for the usage of β-sitosterol include its bioavailability and low targeting effect. As a dietary chemo-preventive and chemotherapeutic agent, β-sitosterol holds good potential. With modern drug delivery systems, the problem of bioavailability can be solved (Wang et al., 2023). There is a great deal of data that supports the fact that β-sitosterol has hundreds of benefits, that are not only being used now but will be used in the future.

8. Conclusion

Most typically found in plants, β-sitosterol is also referred to as “plant sterol ester” and has a variety of uses, including in the medical area and the global food industry. Knowing the structure, biosynthesis, as well as behavior of β-sitosterol requires knowledge of chemistry, biochemistry, and biotechnology. Due to significant health benefits associated with β-sitosterol, these biomolecules need to be provided through diet as the human body is incapable of generating these biomolecules. This substance has a significant impact on human physiology and shares structural similarities with cholesterol. β-sitosterol is been extracted by using technologies like supercritical fluid extraction (SFE), and also by conventional methods of solvent extraction and various chromatographic techniques. Studies have shown that β-sitosterol interferes with a number of cellular signaling pathways, which include cell cycle control, apoptosis, proliferation, survival, invasion, angiogenesis, metastasis, anti-inflammatory responses, anticancer characteristics, hepatoprotective effects, antioxidant activity, cardioprotection, and antidiabetic effects. Despite this, β-sitosterol exhibits minimal toxicity in pharmacological evaluations. It is regarded as the astonishing, more effective drug of the future. Understanding the possible advantages offered by this exceptional phytosterol requires consideration of a wide range of scientific applications.

Consent for publication

All authors agree to publish.

Authors contributions

Azka Khan Durrani contribute for the conception of the paper.

Momina Khalid layout the design of paper.

Awais Raza critically analysis the data.

Izza Faiz ul Rasool done the interpretation of the data.

Waseem Khalid drafting the paper.

Muhammad Nadeem Akhtar revising the paper critically for intellectual content.

Ammar Ahmad Khan also revising the paper critically for intellectual content.

Zunair Abdullah also revising the paper critically for intellectual content.

Babirye Khadijah prepare the final draft of paper and after analysis done the final approval before submission.

Acknowledgments

The authors are gratefully thanking the University of Lahore for their support.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Data availability statement

The authors confirm that the data supporting the findings of this study are available within the article.

Additional information

Funding

There are no funding for this paper.