Fatty Acid and Non-Fatty Acid Components of the Seed Oil of Celastrus paniculatus willd.

ABSTRACT

The yield and chemical composition of the seed oil of Celastrus paniculatus were determined by solvent extraction and gas chromatography-mass spectrometry. The yield of crude fatty oil was found to be 45.5% in the mature seeds on dry weight basis. Fourteen compounds, constituting 97.57% of the oil, were identified. The oil was rich in unsaturated fatty acids (70.11%) followed by saturated fatty acids (25.2%). Oleic acid (54.42%), palmitic acid (20.0%), linoleic acid (15.51%), and stearic acid (4.18%) were the main fatty acids in the oil together with four other minor fatty acids. The current study identifies the novel compounds not previously reported in C. paniculatus oil, including 1,4-benzenediol (0.46%), cinnamic acid (0.15%), 2,6-di-tert-butyl-p-benzoquinone (0.03%), butylated hydroxytoluene (0.4%), and eudalene (0.16).

KEYWORDS:

• Celastrus paniculatus
• Celastraceae
• fatty oil
• oleic acid

Introduction

Forests have been a continuous source of food, medicine, and other products for living beings since time immemorial. Among the forest produce, fats and oils are indispensible ingredients of human and animal diets and industrial products. The non-edible seeds of many Indian plant species of forest origin have been investigated, of which Jatropha curcas Linn., Pongamia pinnata Pierre (Karanj), Azadirachta indica A. Juss (Neem), Scheleichera oleosa (Lour.) Oken (Kusum), Madhuca indica J.F.Gmel (Mahua), Shorea robusta Gaertn, f. (Sal), Salvadora oleoides Decne (Khokan), and Ricinus cummunis Linn. (Castor) have been identified as promising sources of fatty oil with industrial value. But there is a need to identify more sources of fatty-oil-yielding plant species, which can be popularized and promoted as additional sources of fatty oil for edible or biodiesel purpose.

Celastrus (Family: Celastraceae), a genus of shrubs, is distributed over tropical North America, Asia, China, Japan, Australia, and Pacific Islands. Its seven species have been reported to occur in India (CSIR, 1992; Hooker, 1999). Celastrus paniculatus willd., a large woody climbing shrub, is found all over India up to an altitude of 1800 m. Its different parts are used for the treatment of many diseases in the traditional system of medicine in India (CSIR, 1992). Earlier reports showed its use as a laxative, appetizer, emetic, aphrodisiac, brain tonic, and in the treatment of asthma, leprosy, paralysis, leucoderma, rheumatism, gout, and headache (Chopra et al., 1956; Vaidhyaratnam, 1997). Specifically, preparation of the seed constitutes a drug with a bitter taste and unpleasant odor used for the treatment of ulcer, rheumatism, scabies, body and rheumatic pains, wound healing, eczema, beriberi, depression, hysteria, gout, and as tonic, emetic, diaphoretic, and febrifuge. The seed oil is commonly known as Celastrus oil or Malkanguni oil (CSIR, 1992). It is one of the components of the drug ‘Mentat Syrup’ recommended as a memory enhancer and also used for mental disorders (CSIR, 1999; Nadkarni, 1954).

The seed oil is considered as stimulant and mosquito repellant (CSIR, 1992) and used for the burning of lamps (Hooker, 1999). The seed oil showed antibacterial (Patel and Trivedi, 1962), analgesic (Ahmad et al., 1994), antimalarial (Ayudhaya et al., 1987), antispermatogenic (Wangoo and Bidwai, 1988), and antioxidant properties (Ramadan et al., 2009), and anxiolytic activity with no harmful effect (Rajkumar et al., 2007). The oil from the seeds of C. paniculatus has been analyzed in the past and the yields were found to range from 46.0–52.0% (CSIR, 1992; Ramadan et al., 2010; Sengupta and Bhargava, 1970). Earlier studies also showed that palmitic acid (31.2% and 35.5%), stearic acid (3.5% and 6.7%), oleic acid (22.4% and 22.4%), linoleic acid (15.5% and 10.0%), and linolenic acid (22.2% and 14.8%) were the major fatty acids in its oil (Sengupta and Bhargava, 1970; Sengupta et al., 1987). In addition, benzoic acid (3.4%), formic acid (1.5%), and trace amounts of acetic acid have been found in the oil (Sengupta and Bhargava, 1970). The aim of the current study was to elucidate the total oil in C. paniculatus growing in west India and its chemical composition. This information would be useful in determining potential applications of the species for industrial use.

Material and methods

The mature fruits (340 g) were harvested from Celastrus paniculatus, a large woody climber in a botanical garden, Directorate of Medicinal and Aromatic Plants Research, Anand, Gujarat. The seeds were removed from the fruits, dried, and powdered using a home grinder. The powdered seeds (50.0 g) were extracted with hexane using Soxhlet apparatus for 6 hours. The hexane from the crude fatty oil was removed under reduced pressure and the yield of the crude oil was found to be 45.5% (on dried weight basis) and stored at 4 to 8 °C.

The fatty acid methyl esters were prepared using a method described by Rana and Blazquez (2008). Briefly, crude fatty oil (200 mg) was dissolved in 20 ml of sulfuric acid-methanol (1.0%) and refluxed for 2 h on a boiling water bath. The reactions mixture was cooled and dried under reduced temperature. The dried mixture was re-dissolved in 10 ml of distilled water and neutralized with a saturated solution of sodium carbonate. The methyl esters were extracted with diethyl ether and an ethereal layer of fatty acid methyl esters was dried using anhydrous sodium sulphate. Diethyl ether was removed on a heated water bath, cooled, and stored at 4 °C till further analysis.

Analysis of the fatty acid methyl esters was performed on a gas chromatography-mass spectrometry (GC/MS; Focus-PolarisQ, Thermo, Austin, TX, USA) Bench Top Quadrupole Ion Trap Mass Spectrometer equipped with a ZB-5 capillary column (30 m × 0.25 mm i.d., film thickness 0.25 μm). Chromatographic conditions were as follows: the oven temperature was set at 60 °C and programmed at 3 °C/min to 250 °C. Helium was used as the carrier gas at a flow-rate of 1 ml/min (split mode, 1:20); injection volume was 1 μl (12.8 mg in 1 ml of hexane); split flow was 20 ml/min. The injector and transferline temperatures were 220 and 240 °C, respectively. The source temperature of the mass spectrometer was 220 °C. Analysis was carried out in EI mode at 70 eV with the mass range of 40–350 a.m.u range. The identification of the individual compounds (Table 1) were carried out by comparing the retention time and mass spectra with those of authentic samples (Sigma-Aldrich, India) as well as mass spectra in the NIST Mass Spectral Library, U.S. Department of Commerce, Gaithersburg, MD, USA (Ver. 2.0 d 2005) and literature (Adams, 2007).

Table 1. Composition of the crude fatty oil of Celastrus paniculatus seeds.

Peak no.	Compound	Amount (%)
Non-fatty acid components		1.56
1	Benzoic acid	0.36
2	1,4-benzenediol	0.46
3	Cinnamic acid	0.15
4	2,6-di-tert-butyl-p-benzoquinone	0.03
5	Butylated hydroxytoluene	0.40
6	Eudalene	0.16
Fatty acid components		96.01
Saturated fatty acids		25.2
7	Myristic acid	0.62
8	Palmitic acid	20
11	Stearic acid	4.18
13	Eicosenoic acid	0.40
14	Lignoceric acid	0.7
Unsaturated fatty acids		70.11
9	Linoleic acid	15.51
10	Oleic acid	54.42
12	11-Eicosenoic acid	0.18
Percentage of compounds identified		97.57

Results and discussion

The yield of the crude fatty oil was found to be 45.5% in the mature seeds of C. paniculatus on dry weight basis. Fourteen compounds, constituting 97.57% of the oil, were identified (Table 1 and Figure 1). The major portion of the seed oil contained unsaturated fatty acids (70.11%) followed by saturated fatty acids (25.2%). The oil was also found to have aromatic hydrocarbons and their derivatives, which constituted a minor portion (1.56%) of the oil. In this oil, oleic acid (54.42%) and linoleic acid (15.51%) were identified as the main unsaturated fatty acids (Table 1), while 11-eicosenoic acid (0.18%) was present in a lesser amount. Similarly, palmitic acid (20.0%) and stearic acid (4.18%) were major saturated fatty acids with small amounts of lignoceric acid (0.7%), myristic acid (0.62%), and eicosanoic acid (0.4%). In addition to fatty acids, some aromatic compounds, mainly 1,4-benzenediol (0.46%), butylated hydroxytoluene (0.4%), benzoic acid (0.36%), cinnamic acid (0.15%), eudalene (0.16%), and 2,6-di-tert-butyl-p-benzoquinone (0.03%) were identified in the oil.

Figure 1. Total ion chromatogram of fatty oil of Celastrus paniculatus seeds.

Generally, the total oils and chemical composition reported here are similar to those found in earlier studies (CSIR, 1992; Ramadan et al., 2010; Sengupta and Bhargava, 1970). However, contrary to the report by Sengupta and Bhargava (1970) and Sengupta et al. (1987) that found palmitic acid (31–35.5%) to be the major fatty acid in the oil, the current study found oleic acid (54.42%) to be the major fatty acid. This cultivar, found in the region, could be different from previously analyzed and change in oil composition could be due to environmental influence as western India belongs to arid and semi-arid zones with different climate conditions. The amount of palmitic acid (20.0%) exceeded that of stearic acid (4.18%) and was similar to that reported in previous studies (Sengupta and Bhargava, 1970; Sengupta et al., 1987). Linolenic acid, formic acid, and acetic acid identified by Sengupta and Bhargava (1970) were absent in the current study, while 1,4-benzenediol, cinnamic acid, 2,6-di-tert-butyl-p-benzoquinone, butylated hydroxytoluene, and eudalene were reported as minor compounds for the first time in its oil. These aromatic compounds may be responsible for the characteristic aromatic odor of crude fatty oil.

Analysis also showed that the composition of its fatty oil was similar to the edible oils (Agarwal et al., 2003; Chowdhury et al., 2007; Kowalski, 2007; Rana and Blazquez, 2008) and, thus, could be an additional source of edible oil after removal of the odor from the fatty oil by purification.

Comparing the oil content, saturated, and unsaturated fatty acids in the seeds with other Indian edible and non-edible oil seeds, results showed that the oil content in C. paniculatus seeds (45.5%) was higher than that found in Jatropha curcas (30.0–40.0%), Helianthus annuus (25.0–35.0%), Glycine max (15.0–20.0%), and Vernicia fordii (16.0–18.0%). However, it was either equal to or less than oil content in Ricinus communis (45.0–50.0%), Brassica napus (38.0–46.0%), Arachis hypogaea (45.0–55.0%), Elaeis guineensis (30.0–60.0%), Olea europaea (45.0–7.0%), and Cocos nucifera (63.0–65.0%; Aninidita et al., 2010). C. paniculatus seed oil was also found to contain higher amounts of unsaturated (70.11%) fatty acids than that found in rice bran (68.0%), palm (42.2–46.3%), safflower (61.5%), and coconut (7.8%) oils. The amount of unsaturated acids in the oil is comparable to that found in edible oils, such as soyabean, sunflower, mustard, sesame, and olive oils (Table 2; Johnson and Saikia, 2009). Given the similarity between the fatty acid compositions of C. paniculatus oil and that of other edible oils (Agarwal et al., 2003; Chowdhury et al., 2007; Kowalski, 2007; Rana and Blazquez, 2008), it can potentially be used as an additional source of edible oil after removal of the odor from the fatty oil by purification. The amount of oleic acid found in the current study (54.42%) is higher to that found in Jataropha curcas (47.7%) oil (Akbar et al., 2009). Since the seed oil of Jataropha curcas is popular in India for the production of biodiesel, C. paniculatus seed oil has a potential application as a biodiesel.

Table 2. Percentages of saturated and unsaturated fatty acids in the edible oils used in India.

Source of oil	SFAs^z	UFAs^z	Major compound
Soya bean	13.5–16.1	64.2–88.8	Linoleic acid
Sunflower	8.8–16.8	54.8–83.2	Linoleic acid
Groundnut	16.1	71.7	Oleic acid
Mustard	3.6–5.6	58.2–93.6	Erucic acid
Safflower	8.5	61.5	Linoleic acid
Coconut	88.9	7.8	Lauric acid
Sesame	16.8	78.2	Oleic and linoleic acids
Olive	14.2	74.9	Oleic acid
Rice bran	25.4	68.0	Oleic and linoleic acids
Palm	42.5–49.1	42.2–46.3	Palmitic and oleic acids
Celastrus	25.2^y	70.11^y	Oleic and palmitic acids

Note. ^zSFAs = Saturated fatty acids; UFAs = Unsaturated fatty acids.

^yAmounts reported in current study.

Source: Johnson and Saikia (2009).

Conclusion

The seeds and seed oil of C. paniculatus willd. are used for the treatment of various diseases in India. In this study, the seed oil was found to be rich in unsaturated fatty acids. Oleic acid was identified as the main compound instead of palmitic acid. The amount of oleic acid was higher than that in Jataropha curcas oil, which is used for the production of biodiesel in India. Thus, its seeds have the potential to be used for production of biodiesel. The oil of C. paniculatus was found to be similar in fatty acid composition as that of common edible oil, making it a potential edible oil. Furthermore, oil-free seed cake from C. paniculatus can be used as animal feed.

Acknowledgment

The authors are thankful to the Director, Directorate of Medicinal and Aromatic Plants Research, Anand, Gujarat for providing facilities for the current research.