Reveal the phytochemicals of different Pegaga: Centella asiatica and Hydrocotyle verticillata
This study was aimed to reveal the differences of Centella asiatica and Hydrocotyle verticillata. Both species are known as Pegaga in local name and commonly eaten as salad in Malaysia. The phytochemical differences are important to prevent the misuse of the herbs in product development. The key phytochemical groups such as phenolics, flavonoids and terpenoids were estimated from the calorimetric assays, and subsequently identified the intense compounds using LC-MS/MS. The reported triterpenoids (asiatic acid and madecassic acid) and their trisaccharides (asiaticoside and madecassoside) were detected in C. asiatica. Glycosylated quercetin and rhamnocitrin were found in H. verticillata, but absent in C. asiatica. Quercetin and rutin appeared to be the compounds differentiating H. verticillata from C. asiatica based on unsupervised multivariate data analysis. The leaf images of the herbs were compared using a computational edge detection technique. The leaf morphology based on the leaf shape and vein pattern could clearly differentiate the herbs. Therefore, the application of the herbs in product formulation should be careful, since both herbs have different phytochemical profiles which would contribute to different biological activities.