Evaluation of free radical scavenging activity of morel mushroom, Morchella esculenta mycelia: A potential source of therapeutically useful antioxidants

Abstract

Cellular damage caused by reactive oxygen species (ROS) has been implicated in several diseases and antioxidants are known to protect the body from this damage. Antioxidants thus, have gained significant importance in human health. The search for effective, non-toxic natural compounds with antioxidant activity has intensified in recent years. Mycelia of a number mushrooms have recently been successfully used for the development of novel pharmaceutical products. We examined the aqueous-ethanol extract of cultured mycelia of the morel mushroom, Morchella esculenta (L.) Pers. (Morchellaceae) for its ability to scavenge super oxide, hydroxyl, nitric oxide, 2,2′-diphenyl-1-picrylhydrazyl (DPPH), and 2,2′-azino-bis(3-ethylbenzthiazoline-6-sulphonic acid) (ABTS) radicals as well as for inhibition of lipid peroxidation. The extract efficiently scavenged all these radicals and also inhibited lipid peroxidation. Ferric reducing antioxidant power (FRAP) assay indicated the hydrogen donating capacity of the extract. The pulse radiolysis studies using ABTS and carbonate radical (CO₃^•-) showed that the extract significantly carried out the decay of these radicals in a concentration-dependent manner. In conclusion, the investigation showed that the morel mushroom mycelium is an excellent source of antioxidants which are capable of imparting protection at different levels. The findings suggest the potential therapeutic use of morel mushroom, M. esculenta mycelia as an efficient antioxidant.

Keywords::

• Medicinal mushroom
• Morchella esculenta
• mycelia
• antioxidant activity
• pulse radiolysis assay

Introduction

Oxygen, while indisputably essential for life, can also participate in the destruction of tissue and/ or impair its ability to function normally. Oxygen free radicals (OFR), or more generally, reactive oxygen species (ROS) are products of normal cellular metabolism (Valko et al., 2004). ROS are involved in the pathogenesis of a number of diseases. They are usually unstable, reactive and capable of damaging basic cellular structures, such as DNA and cellular membranes. Reactive nitrogen species (RNS), formed in cells as a consequence of oxidative reactions, are also implicated in the pathogenesis of a wide variety of clinical disorders, resulting from deficient antioxidant defenses.

Antioxidants have emerged as a novel class of potential therapeutic agents that scavenge a wide range of reactive oxygen species (Day, 2004). The human body possesses defense mechanisms made of enzymes and endogenous antioxidants which can reduce the oxidative stress. When these defense mechanisms are insufficient, the cellular damage caused by oxidative stress can lead or contribute to several diseases. The ingestion of substances with antioxidant activity can be important in the prevention of oxidative stress and consequently in the prevention of health disorders (Pinto et al., 2005). As synthetic antioxidants have recently been reported to have several drawbacks and possibly be dangerous for human health, the search for effective non-toxic natural compounds with antioxidant activity has gained importance (Gupta & Sharma, 2006). Natural antioxidants from plant origin are considered useful as nutraceuticals due to their beneficial effects on health and disease prevention (Nagochi & Nikki, 2000; Devasagayam et al., 2007; Kamath & Rajini, 2007).

Mushrooms have long been known for their medicinal properties. They are traditionally used in China and Japan for a large number of medicinal purposes (Jong & Birmingham, 1992). Since ancient times they have been used in folk medicine throughout the world (Wasser & Weis, 1999). Mushrooms contain a large number of biologically active components that offer health benefits and protection against many degenerative diseases. A number of medicinal mushrooms have recently been reported to possess significant antioxidant activity (Jose et al., 2002; Jones & Janardhanan, 2000; Ajith & Janardhanan, 2001; Lakshmi et al., 2004). Some of the most recently isolated and identified substances from mushrooms have been reported to possess significant anticancer, cardiovascular, antiviral, antibacterial, antiparasitic, hepatoprotective and antidiabetic activities (Ooi, 2000).

Members of the genus Morchella, commonly known as morels, are one of the most highly priced edible mushrooms in the world (Negi, 2006; Duncan et al., 2002). Morchella esculenta (L.) Pers. (Morchellaceae), an excellently edible mushroom growing in temperate regions, is considered to be a delicacy. In India, species of Morchella, locally known as “guchhi” are found growing in the forests of Jammu and Kashmir and Himachal Pradesh. The preparations from morels are reported to be used in healthcare and for medicinal purposes among traditional hill societies in some parts of India (Prasad et al., 2002). The fruiting bodies of Morchella esculenta were reported to possess antioxidant activity (Elmastas et al., 2006). Since commercial cultivation of morel mushrooms for the fruiting body production has not been largely successful till now, the cultured mycelium is extensively used in food as a flavoring agent. Our previous studies have shown that the cultured mycelia of M. esculenta possess significant antitumor and anti-inflammatory activity (Nitha et al., 2007). In this communication, we report the antioxidant activity of the aqueous-ethanol extract of cultured mycelium of M. esculenta. The activities were determined by various antioxidant assays.

Materials and methods

Production of mushroom mycelium

Culture of Morchella esculenta obtained from the Microbial Type Culture Collection (MTCC 1795), Institute of Microbiology, Chandigarh, India, was employed for the studies. The fungus was grown in submerged culture on potato-dextrose broth (PDB) for the production of mycelia biomass. After ten days of growth in submerged culture on a shaker at 24–25°C, the fungal biomass was harvested, washed thoroughly and dried at 40–50°C (Janardhanan et al., 1970).

Preparation of extracts

The dried mycelia was powered and 100 g of powder was extracted with hot aqueous-ethyl alcohol (ethyl alcohol:water 50/50 v/v) for 8-10 h. The extract was concentrated at low temperature and solvent completely evaporated under vacuum. The residue thus obtained was employed for the experiments.

Chemicals

1,1-Diphenyl 2-picryl hydrazyl (DPPH), 2,4,6-tripyridyl-S-triazine (TPTZ), 2,2′- azinobis (3-ethylbenzothiazolin-6-sulphonic acid) (ABTS) were purchased from Sigma (St. Louis, MO), and ascorbic acid, 2-deoxy ribose, nitroblue tetrazolium, riboflavin, EDTA, ferric chloride, sulfalinamide, naphthylethylenediamine dihydrochloride were purchased from SRL, Mumbai. All chemicals used were of analytical grade.

DPPH radical scavenging assay

In this method, a commercially available and stable free radical (DPPH⁺, 2,2-diphenyl-1-picrylhydrazil), soluble in methanol, was used (Aquino et al., 2001). DPPH in its radical form has an absorption peak at 515 nm, which disappeared on reduction by an antioxidant compound. An aliquot (25 μL) of the extract was added to 1 mL of freshly prepared DPPH solution (0.25 g/L in methanol). Absorbance was measured 20 min after the reaction was started. Radical scavenging activity (RSA) of the extract was calculated using the formula RSA% = (A-B/A) × 100, where A = absorbance of the blank and B = absorbance of the sample (Ramakrishna et al., 2008).

Ferric reducing antioxidant power assay

The ferric reducing ability was measured at low pH (Benzie & Strain, 1996).The stock solution of 10 mM 2,4,6-tripiridyl-S-triazine (TPTZ) in 40 mM HCl, 20 mM FeCl₃.6H₂O, and 0.3 M acetate buffer (pH 3.6) was prepared. The FRAP reagent contained 2.5 mL TPTZ solution, 2.5 mL ferric chloride solution and 25 mL acetate buffer. It was freshly prepared and warmed to 37°C.Then 900 μL FRAP reagent was mixed with 90 μL water and 30 μL test sample/methanol/distilled water. The reaction mixture was then incubated at 37°C for 30 min, and absorbance was recorded at 595 nm. An intense blue complex was formed when ferric tripyridyl triazine (Fe³⁺ TPTZ) complex was reduced to the ferrous (Fe²⁺) form, and the absorbance at 595 nm was recorded. Ferric reducing ability of the extract is calculated using the formula [A-B/A X 100], where A = absorbance of the sample and B = absorbance of blank. The activity is expressed as a percentage.

Assay for superoxide radical scavenging activity

Superoxide radical (O₂^•) generated from the photo reduction of riboflavin was detected by the NBT reduction method of McCord and Fridovich (1969).The reaction mixture contained EDTA (6 mM): NaCN (3 μg); riboflavin (2 μM); NBT (50 μM); KH₂PO₄-Na₂HPO₄ buffer (67 mM, pH 7.8) and various concentrations of extract in a final volume of 3 mL. The tubes were illuminated under incandescent lamp for 15 min. The optical density (OD) at 530 nm was measured before and after illumination. The inhibition of super oxide radical generation was determined by comparing the absorbance values of the control with that of treatments.

Assay for inhibition of lipid peroxidation

Lipid peroxidation induced by Fe²⁺-ascorbate system in rat liver homogenate was estimated by TBA reaction method by Ohkawa et al. (1979). The reaction mixture contained rat liver homogenate 0.1 ml (25% w/v) in Tris-HCl buffer (20 mM, pH 7); KCl (30 mM);FeSO₄ (NH₄)₂ SO₄^• 6H₂O (0.16 mM); ascorbate (0.06 mM); and various concentrations of the extract in a final volume of 0.5 mL. The reaction mixture was incubated for 1 h at 37°C. After the incubation period, 0.4 mL was removed and treated with 0.2 mL sodium lauryl sulfate (SDS) (8.1%); 1.5 mL tert-butyl alcohol (TBA) (0.8%); and 1 mL acetic acid (20%, pH 3.5). The total volume was made up to 4 mL by distilled water and then kept in a water bath at 95–100°C for 1 h. After cooling, 1 mL distilled water and 5 mL n-butanol and pyridine mixture (15:1 v/v) were added to the reaction mixture, shaken vigorously and centrifuged at 4000 rpm for 10 min. The organic layer was removed and its absorbance at 532 nm was measured. Inhibition of lipid peroxidation was determined by comparing the OD of treatments with that of control.

Assay of hydroxyl radical scavenging activity

Hydroxyl radicals generated from Fe³⁺-ascorbate-EDTA-H₂O₂ system (Fenton reaction) was estimated by its degradation of deoxyribose that resulted in thiobarbituric acid reactive substance (TBARS) (Elizabeth & Rao, 1990). The reaction mixture contained deoxyribose (2.8 mM), FeCl₃ (0.1 mM); KH₂PO₄-KOH buffer 20 mM, (pH 7.4) EDTA (0.1 mM); H₂O₂ (1 mM); ascorbic acid (0.1 mM) and various concentrations of the extract in a final volume of 1 mL. The reaction mixture was incubated at 37°C for 60 min. The TBARS formed was estimated by TBA method of Ohkawa et al. (1979). The hydroxyl radical scavenging activity was determined by comparing absorbance of control with that of treatments.

Assay of nitric oxide scavenging activity

Nitric oxide generated from sodium nitroprusside was measured by the Griess reagent by the method of Marcocci et al. (1994). Various concentrations of the extract and sodium nitroprusside (5 mM) in phosphate buffered saline (PBS) in a final volume of 3 mL were incubated at 25°C for 150 min. After incubation, samples (0.5 mL) were removed and diluted with 0.5 mL Griess reagent (1% sulfanilamide, 2% o-phosphoric acid and 0.1% naphthylethylenediamine dihydrochloride). The absorbance of the chromophore formed was measured at 546 nm. The inhibition of nitric oxide generation was estimated by comparing the absorbance values of control with that of treatments.

ABTS+ radical scavenging assay

The assay was carried out by interacting the extract with a model stable free radical derived from 2,2′-azinobis (3-ethylbenzothiazolin-6-sulfonic acid) (ABTS). The production of the radical cation was as described by Long and Halliwell (2001) with some modifications. In brief, a stock solution of ABTS (7 mM) was prepared in water. To this solution ammonium persulfate was added (2.45 mM final concentration) and the solutions were allowed to react for a duration of more than 16 h in darkness at room temperature. ABTS and persulfate react with each other leading to the incomplete oxidation of ABTS to generate ABTS radical. The ABTS radical solution was diluted to an absorbance of 0.75 at 734 nm in PBS and 10 μL of different concentrations of the extract were added to 1 mL of ABTS radical solution. Absorbance was measured spectrophotometrically at 6 min after initial mixing, using PBS as reference.

ABTS radical scavenging assay by pulse radiolysis

Antioxidant activity of the extract was also assayed by ABTS radical scavenging by pulse radiolysis technique using a linear accelerator. The pulse radiolysis system with 7 MeV electrons was used in the present study (Adhikari & Mukherjee, 2002). The dosimetry was carried out using an air-saturated aqueous solution containing 5 × 10⁻² mol dm⁻³ KSCN (Gϵ = 23,889 dm³ mol⁻¹ cm⁻¹ per 100 eV at 500 nm) (Buxton & Stuart, 1995). The width of the electron pulse was 500 ns and the dose was 20 Gy per pulse. Pulse radiolysis study of ABTS radical involves scavenging of primary radicals (^•OH) by azide (N₃^-) producing azidyl radical (N₃^•), which in turn generates ABTS radical in solution. The standard pattern of decay with ascorbic acid having four different concentrations of 5, 10, 15, and 20 μg/mL showed typical concentration-dependent curves (Scotl et al., 1993; Lakshmi et al., 2004). The ascorbic acid equivalent was computed by extrapolating the results with the standard graph.

CO₃^•- radical scavenging assay by pulse radiolysis

In vivo peroxynitrite formation is a diffusion-controlled process and is generated in the reaction between nitric oxide (NO) and O₂^•- radicals (Radi et al., 2001). Peroxynitrite reacts with carbon dioxide (k = 4.6 × 10⁴ M⁻¹ s⁻¹ at pH 7.4 and 37°C) (Denicola et al., 1996), in biological system and forms nitrosoperoxocarboxylate adduct (ONOOCO₂⁻) (Radi et al., 2001), which decays to nitrate and CO₂ with the formation of carbonate radical (CO₃˙) and ^•NO₂ in 33% yields. The one-electron oxidation potentials are: E⁰ (CO₃^•-/CO₃^2-) = 1.78 V and E° (NO₂/NO₂⁻) = 0.99 V, respectively (Lymar et al., 2000). Thus they can mediate a number of peroxynitrite-dependent oxidations (Ford et al., 2002). With this view we studied the reaction of CO₃^•- radical with mushroom extract. The reaction of carbonate radical with mushroom extract was assayed in a solution containing sodium bicarbonate (50 mM) in water with different concentrations (0.01-0.05%) of mushroom extract saturated with N₂O. The CO₃^•- radical is produced in a reaction of ^•OH radical with NaHCO₃. The decay traces were recorded at 600 nm for the CO₃^•- radical thus produced, in the presence and absence of the different concentrations of mushroom extracts.

Results and discussion

The aqueous-ethanol extract was evaluated by assays pertaining to different levels of antioxidant protection corresponding to prevention, interception and repair. FRAP assay relates to prevention of radical formation; DPPH, NO^•,O₂^•− and ^•OH relates to primary radical scavenging and lipid peroxidation measures prevention of membrane damage.

DPPH radical scavenging activity

The extract showed significant DPPH radical scavenging activity. At concentrations of 0.1, 0.5, and 1% the extract scavenged 20.46, 30.96, and 53.79% DPPH radicals (Figure 1). In the DPPH assay the ability of an antioxidant to scavenge stable purple-colored DPPH is tested by its depolarization spectrophotometrically at 595 nm. This explains the second line of defense by antioxidants to suppress chain propagation reaction. The extract also showed significant hydroxyl radical scavenging activity and lipid peroxidation inhibition, and these activities of the extract would make it potentially useful in antioxidant therapy and in therapeutic intervention in diseases involving oxidative stress.

Figure 1.  DPPH radical scavenging activity of the extract. Values are mean ± SD; n = 3.

Ferric reducing antioxidant power (FRAP)

The extract also showed significant ferric reducing power which indicated the hydrogen donating ability of the extract. At concentrations of 0.1%, 0.5%, and 1% the extract reduced 32.71%, 63.38%, and 73.25% ferric radicals, respectively (Figure 2). Non-enzymatic antioxidants react with pro-oxidants and inactivate them. In this redox reaction, antioxidants act as reductants. In this context the antioxidant power can be referred to as reducing ability. In the FRAP assay, an easily reducible oxidant Fe³⁺ is used in excess. Thus on reduction of Fe³⁺-TPTZ complex by antioxidant, Fe²⁺-TPTZ is formed, which can be measured spectrophotometrically at 595 nm. The results show that M. esculenta mycelium extract possessed hydrogen donating capacity indicating the significant reducing power of the extract.

Figure 2.  Ferric reducing power of the extract. Values are mean ± SD; n = 3.

Superoxide radical scavenging activity

The extract effectively scavenged superoxide radicals generated by the photoreduction of riboflavin. The concentration of the extract required to scavenge 50% superoxide anion generated (IC₅₀) was found to be 244 ± 9.62 µg/mL (Table 1). Superoxide radicals generated by the photoreduction of riboflavin reduce NBT to form a purple formazan complex which was measured at 560 nm. The decrease of absorbance at 560 nm with antioxidants indicated the consumption of superoxide radicals in the reaction mixture. Addition of different concentrations of extract to the reaction mixture significantly decreased the absorbance and hence significantly scavenged the superoxide radicals in a dose-dependent manner. The results thus indicate that the aqueous-ethanol extract of Morchella esculenta possessed significant superoxide scavenging antioxidant activity.

Table 1.  In vitro antioxidant activity of M. esculenta mycelium extract.

Activities	IC50 values (µg/mL)
Superoxide scavenging	244.43 ± 9.62
Hydroxyl radical scavenging	363.33 ± 15.27
Nitric oxide scavenging	173.32 ± 11.54
Lipid peroxidation inhibiting	420.00 ± 26.45
ABTS radical scavenging	87.50 ± 4.33

Values are mean ± SD; n = 3.

Hydroxyl radical scavenging activity

The extract was examined for its ability to act as ^•OH radical scavenging agent. The degradation of deoxyribose to TBARS by hydroxyl radicals generated from Fe³⁺-ascorbate-EDTA-H₂O₂ system was markedly decreased by M. esculenta mycelium extract. IC₅₀ value of the extract required to scavenge the generated hydroxyl radical was found to be 363.33 ± 15.27 µg/mL (Table 1). Ferric-EDTA was incubated with H₂O₂ and ascorbic acid to generate hydroxyl radicals, which was detected by their ability to degrade 2-deoxy-2-ribose into fragments that on heating with TBA at low pH form a pink chromogen (Halliwell et al., 1987). Addition of mushroom mycelia extract to the reaction mixture efficiently removed the hydroxyl radicals and prevented the degradation of 2-deoxy-2-ribose in a dose-dependent manner.

Inhibition of lipid peroxidation

The extract effectively inhibited the lipid peroxidation induced by Fe²⁺-ascorbate system in rat liver homogenate. The generation of malondialdehyde (MDA) and related substances that react with thiobarbituric acid was found to be inhibited by the extract and the IC₅₀ value of the extract to inhibit lipid peroxidation was found to be 420 ± 26.45 µg/mL (Table 1). The liver microsomal fractions undergo rapid non-enzymatic peroxidation when incubated with FeCl₃ and ascorbic acid. The use of Fe (III) in the presence of a reducing agent such as ascorbate produces ^•OH and they attack the biological material. This leads to the formation of MDA (malondialdehyde and other aldehydes), which forms a pink chromogen with TBA absorbing at 532 nm. The extract exhibited a strong scavenging effect of hydroxyl radical generated from Fe₂⁻ascorbate system indicating lipid peroxidation inhibiting activity.

Nitric oxide radical scavenging activity

The extract also inhibited the formation of nitric oxide from sodium nitroprusside. Incubation of different concentrations of the extract with sodium nitroprusside solution in PBS resulted in a linear dose-dependent reduction in nitric oxide production. This indicated that extract possessed significant nitric oxide scavenging activity (IC₅₀ 173.32 ± 11.54 µg/mL) (Table 1).

In addition to reactive oxygen species, nitric oxide and reactive nitrogen species are also implicated in inflammation, cancer and other pathological conditions (Sreejayan & Rao, 1997). A potential mechanism of oxidative damage is the nitration of tyrosine residues of proteins, peroxidation of lipids, degradation of lipids and oligonucleosomal fragments. Nitric oxide or reactive nitrogen species formed during its reaction with oxygen or with superoxide such as NO₂, N₂O₄, N₃O₄, nitrate and nitrite are very reactive. Our studies with nitric oxide radical scavenging revealed that the extract is a potent scavenger of nitric oxide radical. The nitric oxide generated from sodium nitroprusside reacts with oxygen to form nitrite. The extract inhibits nitrite formation by competing with oxygen to react with nitric oxide directly and also to inhibit its synthesis.

ABTS radical scavenging activity

The extract efficiently scavenged ABTS radicals generated by the reaction between 2,2′- azinobis (3-ethylbenzothiazolin-6-sulphonic acid) (ABTS) and ammonium persulfate (Figure 3, p <0.01). The activity was found to be in a dose-dependent manner and exhibited an IC₅₀ value of 87.5 ± 4.33 μg/mL (Table 1). ABTS assay is an excellent tool for determining the antioxidant activity of hydrogen-donating antioxidants (scavengers of aqueous phase radicals) and of chain-breaking antioxidants (scavenger of lipid peroxyl radicals). Therefore, the ABTS radical scavenging activity of aqueous–ethanol extract of M. esculenta mycelium indicates its ability to scavenge free radicals, thereby preventing lipid oxidation via a chain-breaking reaction. To elucidate the kinetics of the reaction we continued the study with the pulse radiolysis assay using ABTS radicals.

Figure 3.  Antioxidant activity of aqueous–ethanol Morchella esculenta mycelium extract as measured by ABTS radical scavenging assay. Values are mean ± SD; n = 3.

ABTS radical scavenging by pulse radiolysis

In the pulse radiolysis assay using ABTS radical the extract showed significant activity (Figure 4). The ABTS radical does not decay up to a time scale of 1 min. However, the decay of ABTS radical was observed in presence of the extract, the decay became faster in a concentration-dependent manner. The 2% solution of the extract showed an activity of 3.1 μg ascorbic acid equivalent per mL. The results indicated significant ABTS radical scavenging efficiency of the extract.

Figure 4.  The decay of the ABTS radical was monitored at 734 nm after pulse radiolysis of N₂O-saturated solutions containing NaN₃ (50 mM), ABTS (20 mM) and Morchella esculenta mycelium extract (0–2%).

CO₃^•- radical scavenging by pulse radiolysis

The reaction of carbonate radical with mushroom extract was studied in a solution containing sodium bicarbonate (50 mM) in water with different concentrations (0.01-0.05%) of M. esculenta mycelia extract saturated with N₂O. The decay traces were recorded at 600 nm for the CO₃^•- radical thus produced, in presence and absence of the aforesaid concentrations of extracts (Figure 5). These results indicated that a solution as low as 0.01% of mushroom mycelia extract was able to scavenge more than 90% of the carbonate radical in less than 1 ms. The reactivity of the extract with the CO₃^•- radical was much higher than that with the ABTS radical.

Figure 5.  The decay of the carbonate radical was monitored at 600 nm after pulse radiolysis of N₂O-saturated solutions containing NaHCO₃ (50 mM) and Morchella esculenta mycelium extract.

The results of the investigation reveal that the aqueous–ethanol extract of M. esculenta mycelium possessed significant antioxidant activity. The extract is capable to inhibit free radical formation and can also scavenge them. The antioxidant system comprises different types of functional components classified as first line, second line, and third line defenses. The first line defense comprises preventive antioxidants that act by quenching the radicals and suppressing the formation of free radicals. Our results indicate that the extract has significant hydrogen-donating capacity, the first line of defense which suppresses the free radical formation. DPPH radical scavenging activity of the extract shows its capability as second line of defense.

Antioxidant activity of the edible mushrooms has significant importance because this activity greatly contributes to their nutraceutical properties, thus enhancing their nutritional value. Medicinal mushrooms thus would potentially be useful to help the human body to reduce oxidative damage. The majority of mushroom-derived bioactives has been developed from their fruiting bodies. However, mushroom mycelia for the development of bioactives have been utilized successfully recently. Production of hypoglycemic polysaccharides was successfully achieved by submerged mycelia of Phellinus linteus (Berk. et Curt.) Teng (Hymenochaetaceae) (Kim et al., 2002). Ganoderic acid has been successfully produced from mycelia culture of Ganoderma lucidum Curt. P. Karst (Ganodermataceae) (Fang & Zhong, 2002). Two of the most widely used anticancer polysaccharides, PSK and PSP from Trametes (Coriolus) versicolor (L. Fr.) Lloyd (Polyporaceae) are produced by liquid tank fermentation in Japan and China respectively (Smith et al., 2002).The cultured mycelium of morel mushroom Morchella esculenta is an abundant source of therapeutically useful antioxidants. The findings suggest the potential therapeutic use of morel mushroom mycelia for the prevention of oxidative stress-mediated disease conditions. Our recent investigations reveal that Morchella esculenta mycelia possessed profound nephroprotectve activity (Nitha & Janardhanan, 2008).

Acknowledgement

The authors would like to express their sincere thanks to Dr. D.K. Maurya, Scientific Officer, Radiation Biology and Health Sciences Division, Bhabha Atomic Research Centre, Mumbai, for his valuable help during the experimental designing.

Declaration of interest

The authors declare that there are no conflicts of interest.