Advanced glycation end-products (AGEs) are contributors to several disorders including diabetes and Alzheimer’s disease. For centuries, Ayurvedic herbs have been used for the treatment of these diseases. Herein, the anti-glycative and neuroprotective effects of twenty-three Ayurvedic medicinal plants were evaluated. Since elevated glycation level in vivo is caused by multiple factors including hyperglycemia, oxidative stress, and carbonyl stress, the herbs were also evaluated for total polyphenol content, anti-oxidative activities, and carbonyl scavenging properties. All of the samples (at 100 μg/mL), showed anti-AGE effects ranging from 15.1-90.8%. Pomegranate (Punica granatum) peel and flower extracts showed the most potent inhibitory effects of 90.8 and 86.5% which were higher than positive control, aminoguanidine (AG; 67.2%). Amla (Phyllanthus emblica) juice (85.3%) and moringa (Moringa oleifera) fruit (75.6%) extracts were also superior to AG. To evaluate for neuroprotective effects, the inhibitory effects of the herbs on Aβ1-42 fibrillation were tested by the thioflavin T assay. Bacopa (Bacopa monnieri) showed the highest inhibition (63.5%), followed by gotu kola (Centella asiatica; 62.6%) and moringa seed extract (50.5%). Pomegranate peel and flower, and amla juice extracts inhibited Aβ1-42 fibrillation (49.9, 36.6 and 33.7%) higher than the positive control, resveratrol (31.8%). Interestingly, these plant extracts also showed high polyphenol contents, anti-oxidative activities, and carbonyl scavenging properties. Pomegranate peel extract had the highest polyphenol content (41.2%) among the herbs followed by amla juice extract (38.9%). Pomegranate peel and amla juice extracts also exhibited the strongest methylglyoxal (MGO) scavenging activities by reducing MGO content by 87.3 and 78.6%. In addition, both herbs showed strong anti-oxidative activities (IC50 13.7 and 11.1 μg/mL, respectively). Therefore, the activities of pomegranate and amla may be due to their high polyphenol contents which contributes to their anti-oxidative and carbonyl scavenging properties. Further studies on these promising Ayurvedic herbs are being pursued by our group.

Anti-glycative, reactive carbonyl scavenging and anti-amyloid fibrillation effects of ayurvedic medicinal plants

251st National Meeting (2016)

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