Determination of bioactive compounds and antioxidant activity of Orthosiphon thymiflorus (Roth) Sleesen stem extracts

The present study reports the qualitative and quantitative phytochemical profiling of Orthosiphon thymiflorus stem extracts. The Soxhlet apparatus extracted dried stem samples with petroleum ether, chloroform, ethyl acetate, and methanol. Preliminary phytochemical screening revealed the presence of triterpenoids, steroids, reducing sugar, sugar, alkaloids, phenolic compounds, catechins, flavonoids, saponins, and tannins. The highest total phenolic content was 2.18 mu g/ml in methanol extract, and the highest total flavonoid content was 1.47 mu g/ml in chloroform extract of O. thymiflorus. The FTIR spectra revealed the presence of major functional groups such as phenols, alkanes, amines, alkenes, carboxylic acid & derivatives, arenes, aldehyde, and ketones. The GC-MS study of the stem of O. thymiflorus extracted using various solvents revealed the presence of several bioactive chemicals. Twenty-five compounds were identified in the petroleum ether extract, 18 compounds were identified in the chloroform extract, 28 compounds were found in the ethyl acetate extract, and 11 compounds were found in methanol extract. The crude extracts were further subjected to DPPH scavenging activity of O. thymiflorus, which showed promising results. The present study focusing on profiling of phytochemicals of O. thymiflorus will be useful in the synthesis and preparation of new drugs of pharmaceutical importance.