Procedure for quantitative determination of the amount of flavonoids in pedunculate oak (Quercus robur) leaves

Introduction. Pedunculate oak (Quercus robur L.), a member of the beech (Fagaceae) family, is a medicinal plant. Young tree bark that has astringent and anti-inflammatory properties due to tannins present in the raw material is used as raw material. Other plant organs, oak leaves in particular, are also of interest. The preliminary phytochemical study has shown that they contain flavonoid compounds in addition to tannins. Objective: to develop a procedure for quantitative determination of the amount of flavonoids in the pedunculate oak leaves. Material and methods. The investigation object was pedunculate oak leaves harvested in the Pokhvistnevsky District (Samara Region) in June-August 2019. Direct and differential spectrophotometry was used to develop the procedure. Results. The investigators determined optimal conditions for the quantitative determination of the amount of flavonoids in the pedunculate oak leaves: the extractant was 80% ethyl alcohol; the raw material-extractant ratio was 1:50; the extraction time was 30 minutes, the degree of raw material grinding was 2 mm. Validation studies revealed the validity of the developed procedure. Conclusion. The procedure has been developed for the quantitative determination of the amount of flavonoids in the pedunculate oak leaves calculated with reference to rutin, by using the differential spectrophotometric method at an analytical wavelength of 412 nm. The total flavonoid content in the pedunculate oak leaves ranges from 0.30 to 1.63%.

Quercus robur L, pedunculate oak, Quercus robur L, leaves, standardization, flavonoids, rutin, spectrophotometry