Proximate analysis, phtochemical screening and antioxidant activity of different strains of ganoderma lucidum (Reishi Mushroom)

Ganoderma lucidum, a medicinal macrofungi, has been hailed in the orient since ancient times [1]. Content of numerous biocomponents has allured this mushroom globally [2]. The last decade has witnessed G. lucidum – based pharmaceuticals, cosmetics and toiletries. These are produced from different parts of the mushroom, including mycelia, spores, and fruit body. The specifi c applications and attributed health benefi ts of G. lucidum include control of blood glucose levels, modulation of the immune system, hepatoprotection, bacteriostasis, and more. Though beliefs regarding the health benefi ts of are based largely on anecdotal evidence, traditional use and cultural mores, recent reports provide scientifi c support to some of the ancient claims of the health benefi ts of G. lucidum [3]. More extensive study is called for elucidating the health benefi ts provided by this mushroom especially for the ever increasing food and nutrition oriented therapeutic purposes. In this regard, proximate analysis and phytochemical screening of G. lucidum spur high.


Introduction
Ganoderma lucidum, a medicinal macrofungi, has been hailed in the orient since ancient times [1]. Content of numerous biocomponents has allured this mushroom globally [2]. The last decade has witnessed G. lucidum -based pharmaceuticals, cosmetics and toiletries. These are produced from different parts of the mushroom, including mycelia, spores, and fruit body. The specifi c applications and attributed health benefi ts of G. lucidum include control of blood glucose levels, modulation of the immune system, hepatoprotection, bacteriostasis, and more. Though beliefs regarding the health benefi ts of are based largely on anecdotal evidence, traditional use and cultural mores, recent reports provide scientifi c support to some of the ancient claims of the health benefi ts of G. lucidum [3]. More extensive study is called for elucidating the health benefi ts provided by this mushroom especially for the ever increasing food and nutrition oriented therapeutic purposes. In this regard, proximate analysis and phytochemical screening of G. lucidum spur high.
Oxidative stress (OS) stands at the root of multiple diseases. Thus, search for potent antioxidant has got momentum. Ganoderma lucidum has been reported possessing antioxidant prowess of different sorts. Its antioxidant capacity varies from strain to strain even from parts to parts of the same strain. There is hardly any study reporting the proximate analysis, phytochemical screening and antioxidant studies of different strains and mix of different strains of this mushroom. Thus, the present study has been aimed at elucidating these unraveled issues of two strains named arbitrarily as 5 and 7 of G. lucidum and their mix. national mushroom development institute and cut into small pieces. Small pieces were dried under the sun followed by hot air oven at the temperature 55°C until proper drying. After drying, the dried chips were ground into coarse powders using blender having high capacity grinding power. Then the powder were stored in air tight container with necessary markings for identifi cation and kept in cool, dark and dry place for further investigation. Hot water extract (HWE) of G. lucidum was prepared following the method of Rahman, et al. (2016) [4].

Proximate analysis
Following the procedure established by the Association of Offi cial Analytical Chemists (AOAC), the analyses were performed [5]. Analyses included the determination of crude protein, crude fat, ash, crude fi ber, moisture and carbohydrate.
The percentage of all the fractions (crude protein, crude fat and ash) were added together and subtracted from 100 to obtain the total carbohydrate percentage.

I.
Qualitative screening for antioxidant activity

Reducing sugar content assay
Following the modifi ed method of Nelson-Somogyi (1944) [13], content of reducing sugar in the HWE of G. lucidum was performed.

Antioxidant assay
Ferric reducing antioxidant power (FRAP) assay Following the modifi ed method of Benzie and Strain (1996) [14], ferric reducing antioxidant power (FRAP) assay of the HWE of G. lucidum was performed.

Statistical analyses
All the experiments were performed in triplicate and the data presented as mean ± SEM. Statistical package SPSS version 20 was used. Analyses were carried out using one-way analysis of variance (ANOVA) and the differences among means were further analyzed by least signifi cance difference (LSD) at 95% level ( ≤ 0.05).

Proximate composition
Carbohydrate content per 100 gm of strain 5, 7 and mix had been found to be 37.18 gm, 51.65 gm and 44.91 gm, respectively (

Phytochemical and antioxidant content
As shown in Table 2, content of ascorbic acid, total polyphenol, total fl avonoid, reducing sugar was higher in G. lucidum 7 is higher than that of the 5. Our fi ndings show close proximity with those of Breene (1990) [16]. However, compared with those of Chang and Buswell (1996) [17], fi bre and ash content were found higher and carbohydrate and lipid content were found lower in in this study.This variation may be due to the different growth of the strains. Also, growth substrate, the method of cultivation, stage of harvesting and time interval between harvest and measurement methods might contribute to variation in the nutritional status of the mushroom strains.
Content of ascorbic acid was also higher in G. lucidum 7 than that of the 5. Ascorbic acid is a strong antioxidant that directly interacts with a broad spectrum of harmful reactive oxygen species, terminates the chain reaction initiated by free radicals via electron transfer, and is involved in the regeneration of other antioxidants, to their functional state.
Total phenolics content (TPC) and total fl avonoids content were also higher in the G. lucidum 7 than that of the 5.
Phenolic acid is the main phenolic compounds in mushrooms.
Ganoderma-based other phenolics include gallic acid, tannic acid, protocatechuic acid and gentisic acid [4]. Flavonoids are the plant pigments responsible for plant colors and exert their health-promoting activities through their high pharmacological potentials as radical scavengers [4]. Flavonoids are the antioxidants that can prevent or delay the oxidation of substrates even when it is present in low concentrations, so as to prevent oxidation by the pro-oxidants (ROS and RNS).