Speaker
Description
The increasing global prevalence of microbial infections, oxidative stress, and inflammatory disorders necessitates the development of novel therapeutic agents with minimal side effects. Plant-derived medicines, particularly those rich in bioactive compounds like phenolics and flavonoids, offer promising alternatives. Azadirachta indica (neem), a widely used medicinal plant in traditional medicine, contains diverse phytochemicals with potential therapeutic properties. This study aimed to evaluate the in vitro anti-inflammatory, antioxidant, and antimicrobial activities of the total phenolic and flavonoid extracts from neem leaves. The leaves were subjected to methanol extraction (80% methanol acidified with 1% formic acid) for free phenolics, followed by base and acid hydrolysis to isolate bound phenolics. Phytochemical screening confirmed the presence of flavonoids, triterpenes, saponins, phenolic compounds, etc. Total phenolic content (TPC) and total flavonoid content (TFC) were quantified, with base-hydrolysable phenolics exhibiting the highest levels (33.62 mg GAE/g DW and 61.91 mg QE/g DW, respectively). Antioxidant activity, assessed via DPPH radical scavenging, revealed that base-hydrolysable phenolics had the strongest activity (IC50 = 19.78 µg/mL), surpassing ascorbic acid (IC50 = 21.94 µg/mL). Anti-inflammatory evaluation using a protein denaturation assay demonstrated that base-hydrolysable phenolics (IC50 = 25.16 µg/mL) were more potent than diclofenac (IC50 = 109.6 µg/mL). However, none of the extracts exhibited antimicrobial activity against selected bacterial (E. coli, S. typhi, S. aureus, S. saprophyticus) and fungal (C. albicans, C. glabrata) strains at 100 mg/mL. These findings highlight the significant antioxidant and anti-inflammatory potential of neem leaf phenolics, particularly base-hydrolysable fractions, suggesting their therapeutic value in oxidative stress and inflammation-related disorders. Further studies are needed to optimize extraction methods and explore in vivo efficacy and mechanisms of action.
Keywords: Azadirachta indica, phenolics, flavonoids, antioxidant, anti-inflammatory, antimicrobial, phytochemicals.