Direct sunlight and partial shading alter the quality, quantity, biochemical activities of Kaempferia parviflora Wall., ex Baker rhizome essential oil: A high industrially important species

Kaempferia parviflora Wall., ex Baker is a perennial plant with numerous medicinal properties. Different light intensity is known to produce variable results in crops. Keeping in view the importance of the plant, the aim of the present study was to evaluate the effect of direct and partial sunlight on K. parviflora essential oil yield, chemical profile as well as biological activities. For direct sunlight conditions K. parviflora were planted in an open field and for partial shade (75% sunlight) under a green polyethylene agro shade net during the year 2020. The essential oils extracted by hydrodistillation were chemically profiled by gas chromatography/mass spectroscopy (GC/MS) which revealed linalool as the major compound in both K. parviflora essential oil under shade cultivation (KPEOSH) and K. parviflora essential oil under direct sunlight cultivation (KPEOS) with significantly higher linalool content in KPEOSH (43.35%). The essential oil yield of KPEOSH (0.92% w/w) was found to be higher than KPEOS (0.76% w/w). The essential oils were analyzed for antioxidant, anti-inflammatory, antimicrobial, anti-cholinesterase, tyrosinase, anti-diabetic, and genotoxicity properties. Both the KPEOSH and KPEOS exhibited superior activities than the standards for the antioxidant, anti-inflammatory, anti-cholinesterase, tyrosinase, and antidiabetic properties. However, both the essential oils possessed inferior antibacterial and weak antifungal properties. Considering the genotoxicity assay, both the essential oils were found to be non-toxic. The essential oils can be analyzed for further pharmaceutical applications considering their higher biological activity as compared with standards. The present investigation suggested that partial shade conditions give higher essential oil yield than open field conditions.