Response surface methodology (RSM), based on the central composite design (CCD), was used for the systemic optimization of galactomannan (GAL) extraction from Trigonella foenum-graecum. GAL was reported to possess a variety of pharmacological effects and is commercialized as adjuvant therapy for diabetes, obesity, and hypercholesterolemia. Seven process variables were evaluated (12 experiments in a Plackett-Burman design) to screen the significant factors affecting the extraction yield. The three most significant variables were evaluated in CCD at two levels (twenty experimental designs) to obtain the utmost percentage yield. The yield of GAL extraction was influenced by the volume of the precipitating solvent to the volume of the soaking water and reached a maximum of 10.1% at a ratio of 3.633:1. Exploring the antioxidant, cytotoxic, and anti-microbial activities of GAL revealed cytotoxic activity against LS174-T colorectal cancer cells, weak antioxidant activity, and moderate antimicrobial activity against Candida tropicalis and Micrococcus species.
Keywords: Galactomannan; Trigonella foenum-graecum; antimicrobial; antioxidant; cytotoxic; response surface methodology.