Pharmacological and Phytochemical Evaluation of Shikakai (Acacia concinna) and Ritha (Sapindus mukorossi): Antioxidant, Antimicrobial, and Hair Growth–Promoting Activities

Abstract

Background: Shikakai (Acacia concinna) and Ritha (Sapindus mukorossi) are two plants widely used together in traditional Ayurvedic hair care, but comparative data on their phytochemistry and bioactivity under matched experimental conditions are limited. Methods: Aqueous and ethanolic extracts of Shikakai pods and Ritha pericarp were screened qualitatively for major phytochemical classes and profiled by gas chromatography–mass spectrometry (GC–MS), then evaluated for 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical-scavenging activity and total antioxidant capacity (TAC), antibacterial activity against Staphylococcus aureus, Escherichia coli, and Pseudomonas aeruginosa (agar well diffusion and broth microdilution), antifungal activity against Candida albicans and Candida tropicalis (broth turbidity assay), cytotoxicity on L-929 fibroblasts (MTT, LDH, and neutral red uptake assays), and hair-growth-related activity on human hair follicle dermal papilla cells (BrdU incorporation, IGF-1 and VEGF secretion) together with in vitro 5α-reductase inhibition. Results: Both extracts contained saponins, flavonoids, tannins, terpenoids, coumarins, and phytosterols; GC–MS identified glycidyl oleate as a major Shikakai constituent and cis-vaccenic acid as a major Ritha constituent. Shikakai showed a marginally lower DPPH IC50 (~50 µg/mL) than Ritha (~60 µg/mL) and a marginally higher TAC (75 ± 5 vs 68 ± 4 mg ascorbic acid equivalents/g), neither difference reaching statistical significance (p > 0.05). Ritha produced larger inhibition zones and lower minimum inhibitory concentrations than Shikakai against all three bacterial strains (e.g., 4 vs 8 mg/mL for S. aureus) and inhibited Candida growth by 67–85% at 5 mg/mL, compared with 15–17% for Shikakai. Neither extract reduced L-929 viability below 80% at 200 µg/mL. Both extracts increased dermal papilla cell proliferation relative to control (Shikakai ~120%, Ritha ~130%; minoxidil ~150%), increased IGF-1 and VEGF secretion, and inhibited 5α-reductase activity by up to 45–50% at 200 µg/mL. Conclusion: Under these in vitro conditions, Shikakai and Ritha extracts showed antioxidant, antimicrobial, and hair-follicle-related activity with no marked L-929 cytotoxicity at the hair-assay