LC-MS/MS analysis and antioxidant activity of crude extracts from Cistus incanus L

Cistus incanus L, also known as rockrose, is used to treat various health disorders. The objective of the present work is to identify major constituents of the methanol and n-butanol extracts of C. incanus using LC-MS/MS analysis. Antioxidant activity was also evaluated using the DPPH^. radical, ABTS^+. and FRAP assays. The methanol extract was subjected to column chromatography, affording β-sitosterol glucoside, reported here for the first time from C. incanus. A total of 26 targeted chemicals were identified in the n-butanol extract, in which catechin appeared as the predominant flavonoid (36.9 mg/g extract); on the other hand, 3-O-Methylquercetin (59.4 mg/g extract) was the major flavonoid in the methanol extract. Antioxidant activity of the n-butanol extract exhibited superior radical scavenging activity on DPPH^. radical (IC₅₀ =31.1 ± 1.5 μg/mL), for the ABTS⁺ radical (IC₅₀ =51.2 ± 2.0 μg/mL), and (IC₅₀ =31.1 ± 1.2 μg/mL) for the FRAP assay.