Phytochemical composition and bioactivities of the Endemic Sideritis sipylea Boiss Greek Species

Sideritis sipylea Boiss. (Fam. Lamiaceae), commonly known as ironwort, is an endemic plant of the North Aegean Islands (Greece), traditionally used as aerial part decoction or infusion for the treatment of different ailments, especially common cold and gastrointestinal disorders, despite few pharmacological basis [1]. This is an important issue considering that medicinal plants still maintain an important role in the Greek therapy, especially for populations growing in the wild [2]. In the attempt to improve the available scientific knowledge, in the present study we explored the phytochemical composition and bioactivities of the aerial parts from S. sipylea Lesvos Island. To this end, a chromatographic fractionation of a S. sipylea methanolic extract, using ethyl acetate with 10 (S10), 20 (S20), and 50% (S50) methanol, was performed. The obtained samples were phytochemically analyzed by applying spectrophotometric and chromatographic methods [2,3]. Moreover, their scavenger activity towards DPPH, ABTS, and nitric oxide radicals, and the inhibition of advanced glycation end-products (AGE) formation have been investigated [4]. At last, the antioxidant, cytoprotective, and antiproliferative properties were evaluated in human normal and malignant cell lines by MTT and Neutral Red assays [4]. The phytochemical analysis highlighted the presence of flavonoids, iridoids, and phenolic acids in all the tested samples. Particularly, the S10 fraction was mainly characterized by iridoids, while S20 and S50 by lavandulifolioside and chlorogenic acid, respectively. Under our experimental conditions, all the samples were able to scavenge DPPH, ABTS, and nitric oxide radicals, being S10 fraction the most potent; moreover, a moderate inhibition of AGE formation was highlighted for S10 and S20. These fractions were also the most effective to counteract the oxidative damage induced by tBOOH in normal cholangiocytes, by reducing ROS levels and affecting GSH antioxidant system. Conversely, only S10 was able to reduce cancer cell viability, being most potent in pancreatic cancer cells BxPC3. Overall, the present findings highlight that S10 and S20 fractions from S. sipylea possess promising biological activities which could support the traditional use of this endemic Greek species and encourage further studies for future pharmaceutical applications. References [1] Axiotis et al., Front. Pharmacol. 2018, 9, 409. [2] Axiotis et al., Molecules 2020, 25, 2022. [3] Di Sotto et al., Journal of Functional Foods 2018; 40: 679-691. [4] Di Sotto et al., Molecules 2019; 24(17):3103.