Studies on secondary metabolite profiling, anti-inflammatory potential, in vitro photoprotective and skin-aging related enzyme inhibitory activities of Malaxis acuminata, a threatened orchid of nutraceutical importance.

J Photochem Photobiol B. 2017 Aug;173:686-695. doi: 10.1016/j.jphotobiol.2017.07.010. Epub 2017 Jul 12. Bose B1, Choudhury H2, Tandon P1, Kumaria S3. Author information 1 Plant Biotechnology Laboratory, Department of Botany, North-Eastern Hill University, Shillong 793022, Meghalaya, India. 2 Biotechnology Laboratory, Unit of Biotechnology, School of Technology, Department of Basic Sciences and Social Sciences, North-Eastern Hill University, Shillong 793022, Meghalaya, India. 3 Plant Biotechnology Laboratory, Department of Botany, North-Eastern Hill University, Shillong 793022, Meghalaya, India. Electronic address: sumankhatrikumaria@gmail.com. Abstract Malaxis acuminata D. Don., a small, terrestrial orchid, is endemic to tropical Himalayas at an altitude of 1200-2000m asl. The dried pseudobulbs are important ingredients of century old ayurvedic drug 'Ashtavarga' and a polyherbal immune-booster nutraceutical 'Chyavanprash', known to restore vigour, vitality and youthfulness. Considering tremendous medicinal importance of this threatened orchid species, a detailed study was undertaken for the first time to address its antioxidant potential, secondary metabolite contents and biological activities against skin-aging related enzymes (anti-collagenase, anti-elastase, anti-tyrosinase and xanthine oxidase) and anti-inflammatory activity (5-lipoxygenase and hyaluronidase) in different plant parts of wild and in vitro-derived plants of M. acuminata. Methanolic leaf and stem extracts were further evaluated for in vitro photoprotective activity against UV-B and UV-A radiations. Furthermore, secondary metabolite profiling of various plant parts was carried out by Gas Chromatography Mass Spectrometry (GC-MS). A significantly higher antioxidant potential (DPPH, metal chelating and ABTS•+) with a comparative higher yield of secondary metabolites was observed in in vitro-derived plantlets as compared to the wild plants. Among various solvent systems used, methanolic leaf and stem extracts showed promising inhibitory activity against major skin aging-related enzymes and anti-inflammatory potential. Methanolic leaf and stem extracts of both wild and in vitro-derived plants showed promising photoprotective activity against UV-B and UV-A radiations in vitro with comparatively higher sun protection factor (SPF). Furthermore, GC-MS analysis of methanolic extracts of leaves and stems of wild as well as in vitro-derived plantlets revealed presence of many bioactive metabolites such as, dietary fatty acids, α-hydroxy acids, phenolic acids, sterols, amino acids, sugars and glycosides which substantially explain the use of M. acuminata as one of the potential rejuvenator and anti-aging ingredient in many Ayurvedic formulations. KEYWORDS: Anti-aging; Anti-inflammation; Antioxidant; Chyavanprash; Malaxis; Photoprotection; Ultraviolet radiation PMID: 28743100 DOI: 10.1016/j.jphotobiol.2017.07.010