Identification of potential source of quality raw material of Costus speciosus from Western coast of Malabar

Costus speciosus is a medicinally important plant due to its diosgenin content. It is widely used as ingredient in different herbal formulations. The present study aimed to assess eleven germplasms (rhizomes) for elite source of diosgenin content by the evaluation of pharmacognostical and pharmacological potential. It was further correlated with existing edaphic factors of respective rhizospheric soil collected from varied geographical conditions of western coast of Malabar. Pharmacognostical study was evaluated as per the Ayurvedic Pharmacopoeia of India guidelines. For quantification of the bioactive compound diosgenin, a standard method was developed for high-performance thin-layer chromatography (HPTLC). The pharmacological potential of each collected germplasm was analyzed by starch–iodine assay for anti-diabetic activity and protein denaturation model for anti-inflammatory activity. The findings of morpho-anatomical studies revealed no significant variation among the collected samples. For diosgenin content, HPTLC was performed on silica gel 60 F 254 by using the mobile phase n -hexane–ethyl acetate (7:2, V/V ) with R F value 0.23. HPTLC quantification revealed that the content of diosgenin varied from 0.036 to 1.069% having a maximum content in NBCS-123 from Kozhikode, Kerala. In the anti-diabetic assay, the IC 50 value of sample was found to be maximum in NBCS-128 (95.18 ± 0.61 µg/mL) and in the anti-inflammatory assay, IC 50 value for inhibiting protein denaturation was found to be maximum in NBCS-121 (90.43 ± 2.26 µg/mL). The present study is relevant to explore the possibility of elite sources as quality planting material for locations of specific commercial cultivation leading to quality raw material required to herbal drug industry.