Estudo fitoquímico e avaliação antineuroinflamatória de Senna pluribracteata, uma nova espécie brasileira da família Fabacea

Abstract

Since the earliest civilizations, humans have used plants for food, construction, and disease treatment, with the Fabaceae family representing an important source of species with therapeutic properties. In Brazil, the genus Senna is widely distributed, especially in the Atlantic Forest, and holds great relevance in ethnomedicine due to the richness of its bioactive metabolites. In this context, this study aimed to expand knowledge about the Senna genus, specifically the species Senna pluribracteata, a newly identified species, by isolating its chemical constituents and evaluating its antineuroinflammatory potential. The aerial parts of the plant were dried, ground, and subjected to an ethanol extract (EEB), followed by a liquid–liquid partitioning (CLV) to fractionate this extract. The 100% ethyl acetate (AcOEt) and AcOEt:MeOH (1:1) phases, after being subjected to MPLC and HPLC, led to the isolation of several

compounds. From the 100% AcOEt phase, sennaquinone A (Sep-1), vanillic acid (Sep- 8), protocatechuic acid (Sep-9), resveratrol (Sep-11), and vomifoliol (Sep-12) were

isolated. From the AcOEt:MeOH (1:1) phase, quinquangulone (Sep-2), quinquanguline-6-O-[α-L-rhamnopyranoside-(1→6)-β-D-glucopyranoside] (Sep-3),

rubrofusarin-6-O-[β-(6'-(E)-crotonylglucopyranoside)] (Sep-4), rubrofusarin-6-O-[α-L- rhamnopyranoside-(1→6)-β-D-glucopyranoside] (Sep-5), rubrofusarin-6-O-β-D- glucopyranoside (Sep-6), norrubrofusarin-6-O-β-D-glucopyranoside (cassiaside)

(Sep-7), and quercetin-3-O-sambubioside (Sep-10) were obtained. The compounds

were identified by high-resolution electrospray ionization mass spectrometry (HR-ESI- MS) and 1H and 13C NMR spectroscopy, using one- and two-dimensional techniques.

Antineuroinflammatory activity was assessed through a cell toxicity assay (MTT reduction) using the BV2 microglial cell line, along with nitric oxide (NO) production measurement. Treatment with Sep-2, Sep-3, Sep-4 (200 μM), and Sep-3 (100 μM) reduced cell viability by more than 20%, and only Sep-5 significantly reduced NO levels. The results obtained in this study contributed to the phytochemical and pharmacological knowledge of the Senna genus and of the new species Senna pluribracteata.