Standardization of Gum resin of Shorea Robusta Gaertn and Evaluation of Anti - Microbial & Anti - Oxidant Activity of its Isolated Compounds

Abstract

Dipterocarpaceae plant has received much attention since they produce many complex compounds that are useful in food as herb and potential antimicrobial agent. They are rich source of oligomeric stilbenes previously reported inhibitor of 5α reductase39, scavenger of superoxide40 and cytotoxic agents41. Many triterpenoids like asiatic acid55, oleanane and ursane56 are very good anti bacterial agents. The gum resin of Shorea robusta is kwon to rich source of triterpenoids49-50. In present study chemical constitutes of gum resin of S.robusta was isolated by vacuum assisted column chromatography and standardization parameter for gum resin of S.robusta was established. The essential oil from resin was also collected by dry distillation47 and its HPTLC chromatographic fingerprinting also established. The antimicrobial and antioxidant activity of isolated compounds and oil were also evaluated. Standardization of authenticated sample of gum resin of S.robusta was done by morphological study, microscopical study of powder materials and physicochemical parameter like ash values, extractive values and loss on drying. Extracts from gum resin of S.robusta were prepared by refluxing with methanol49 and Hexane: Ethyl Acetate: Methanol (1:1:1) 50. The methanolic crude extract isolated by vacuum assisted column chromatography. FTIR, H1-NMR, MASS spectrum of isolated compounds was recorded for identification and characterization. Spectral data suggest compounds are mainly pentacyclic triterpenoids. Extensive work is under process for detail structure elucidation of isolated compounds. Quantitative method were developed using silica gel silica gel F254 precoated plates, automated band wise sample application, detection with specific reagent, automatic dentiometric determination for variety of constituents present in extracts. There were two different methods developed for estimation of sr001 and sr009 from methanolic extract of resin samples. The methods were validated for linearity, accuracy, precision and specificity. In both methods sr001 and sr009 resolved in single run with single mobile phase system. Further developed HPTLC method isfirst attempt to establish qualitative and quantitative analysis aid standardization of resin which is highly valued in traditional system of medicine for multiple uses. The essential oil was collected from resin samples by dry distillation method. Traditionally oil obtained from dry distillation was used for wound healing purpose47. The HPTLC chromatographic fingerprinting was developed assessment of quality of oil sample. FTIR spectrum of oil sample was also recorded for identification of oil samples. HPTLC fingerprinting of oil obtained from dry distillation of resin is also first attempt to establish quality control tool for standardization of oil samples. The gum resin of S.robusta was traditionally used for wound healing purpose44-47. The wound healing potential of S.robusta was might be due to its antimicrobial potential. Isolated compounds and essential oil were evaluated for antimicrobial activity against gram positive (S.aureus), gram negative (E.coli) and fungal (A.niger) species. In conclusion our data suggest that oil having well antimicrobial potential while isolated compounds alone does not having significant antimicrobial potential. Antioxidant potential of isolated compound and methanolic extract of resin was evaluated. In conclusion our data suggest that neither isolated compounds nor methanolic extract of resin having antioxidant potential. Further, detailed pharmacological screening will be planed to identify the efficacy of the compounds in wound healing process.