Evaluation of Polyphenolic Compounds and Biological Activities of Aesculus indica Seeds

Background: Aesculus indica (Indian horse chestnut), locally called jawaz is a tall, deciduous and shady tree, belonging to family Hippocastanaceae. This is a medicinal plant rich in natural compounds like polyphenols that may have strong health benefits. Objective: To evaluate the biological potential and polyphenolic profile of Aesculus indica seed and peel extracts against antibacterial, antifungal, insecticidal and nematocidal activities. Methodology: Seeds of the Aesculus indica were collected from the local markets of the Swat Valley. After the extraction and fractionation, the methanolic extract of the seed was used against pathogens. Results: The antibacterial activity of methanolic seed extract was strong, with inhibition zones of 13.83 mm for K. pneumoniae, 13.93 mm for S. aureus, 15.00 mm for P. mirabilis, and 13.03 mm for E. coli at 50 µl/ml. The highest inhibition of 22.93 mm against K. pneumoniae was recorded by methanolic peel extract. In contrast, the hexane fraction showed weak inhibition (1.97–5.97 mm). The highest inhibition of methanolic extracts at 50 µl/ml was 22.70 mm for A. niger, 15.13 mm for F. solani, and 19.07 mm for C. albicans, indicating strong antifungal activity as well. For Tribolium castaneum, insecticidal tests indicated 80% death at 1000 ppm, but nematocidal testing showed 30% mortality at 24 hours and around 60% at 48 hours at 300 ppm. Three main phenolic compounds were found by HPLC analysis: mandelic acid, quercetin, and phloroglucinol. The most prevalent of them was mandelic acid. Conclusions: Overall, the results show that Aesculus indica has strong antibacterial, antifungal, insecticidal, and nematocidal properties due to its abundance of bioactive polyphenols.