FTIR spectra-based fingerprinting and chemometrics for rapid investigation of antioxidant activities of medicinal plants

Various plants have been used as herbal medicines by the community since they contain a lot of phytochemicals having the beneficial effect to human health including flavonoids and phenolic compounds. The objective of this study was to evaluate the antioxidant activities, determine the levels of total phenolics and flavonoids contents in selected medicinal plant extracts and fractions. The plants were extracted with methanol, then fractionated with n-hexane and ethyl acetate to get extracts and its fractions. The extracts were subjected to FTIR spectral measurements antioxidant activities evaluation as well as total phenolics and total flavonoids contents. Furthemore, FTIR spectra assisted by chemometrics were used to predict these antioxidant activities. Ethyl acetate fraction of medicinal plants provided the strongest antioxidant activities with high levels of total phenolic and flavonoids. Partial least square regression (PLSR) using variable of absorbance values at 3600 â�� 650 cm^-1 exhibited good correlation between actual values of antioxidant activities (IC<inf>50</inf>) and predicted values with R² values of 0.9974 and 0.9983 in calibration and validation models, respectively. Furthermore, the low values of RMSEC (0.706) and RMSEP indicate that the developed models were precise enough to predict the antioxidant activities. The combination of FTIR spectroscopy and PLSR offered the accurate and precise models for the prediction of antioxidant activities of studied extracts and fractions of studied plants. © 2025 Marmara University Press.