GC-MS Analysis, Determination of Total Flavonoid Content, Sun Protection Factor, and In Vitro Anti-inflammatory Activity of Ethanol Extract of Kokang (Lepisanthes amoena) Leaves

Lepisanthes amoena, locally known as kokang, is an indigenous plant from Kalimantan. The plant is traditionally used by the Dayak and Kutai tribes in East Kalimantan (Indonesia) for the treatment of skin inflammation. This study aimed to determine the phytochemical constituents, total flavonoid content, sun protecting factor (SPF), and anti-inflammatory activity of the ethanol extract of L. amoena leaves. Powdered L. amoena leaves were extracted by maceration in 96% ethanol. The chemical constituents of the extract were identified by gas chromatography-mass spectrometry (GC-MS). Total flavonoid content was determined using colorimetric method. The determination of sun protecting factor (SPF) was carried out using a UV-Vis spectrophotometer at a wavelength range of 290-320 nm. Anti-inflammatory activity was tested using the protein denaturation inhibition assay. GC-MS analysis identified five key volatile constituents, with Benzyl (1,2,3-thiadiazol-4-yl) carbamate (29.37%) identified as the major compound. The total flavonoid content of ethanol extract of L. amoena leaves was 7.105 ± 0.065% w/w QE. Results of the SPF determination indicate that L. amoena leaf extract has "ultra" UV-protection activity at 850–950 ppm with SPF values ranging from 16.351 to 20.543. The ethanol extract of L. amoena leaves exhibited strong anti-inflammatory activity, with IC₅₀ value of 18.933 ppm in the protein denaturation inhibition assay, which was significantly lower than that of diclofenac sodium (IC₅₀ = 23.006 ppm). These findings suggest that L. amoena leaf extract holds potential as a natural source of anti-inflammatory and photoprotective agents.