The study of multiple extraction methods of phytochemical constituents of senna alata leaves

Abstract

The demand for “Gelenggang” scientifically named Senna alata Linn-based product, is increasing due to the well-known therapeutic properties that can treat various diseases such as skin disease, ringworm, and constipation. Various extraction methods have been used to study the active ingredients and find scientific evidence for their herbal activities. Thus, this study aims to investigate the difference in yield percentage, phytochemicals, antioxidant and antimicrobial activities of different extracts of S. alata leaf. The extraction methods used in this study were maceration, Soxhlet, and Subcritical Carbon Dioxide Soxhlet (SCDS), our findings suggested that conventional methods yield higher percentages of extracts compared to SCDS ranging from (1.20 ± 0.417e %) to (25.14 ± 1.017a %) with methanol extraction showed higher yields than hexane extraction, indicating the solvent's influence on extraction efficiency. The study also explores the effect of sample: co-solvent ratio on the yield of extracts using SCDS (1.20 ± 0.417e to 2.45 ± 0.417e %). GCMS analysis reveals the presence of eighteen compounds, with phytol acetate, dihydroactinidiolide, and hexadecenoic acid methyl ester identified as major constituents. The extracts exhibit in vitro antioxidant activity by the DPPH assay with the SCDS extract using methanol as the soaking solvent showing the strongest potency (IC50 value = 0.693 ± 0.1725 mg/ml), while the weakest also from SCDS method but ethanol as co-solvent with highest IC50 value (55.569 ± 2.29 mg/ml). On the other hand, agar disc diffusion assay resulted that methanolic extracts from Soxhlet showed the most significant inhibition zones against Staphylococcus aureus ATCC25923 which ranges from 9 to 11 mm. Furthermore, the resazurin-based microdilution techniques yielded the lowest MIC and MBC value from both methanolic Soxhlet extracts against K. pneumoniae (20.75 mg/ml). Overall, this research highlights the potential of SCDS as a promising extraction method for S. alata leaves, with potential to preserve bioactive constituents despite lower yield percentages compared to conventional methods.