New sesquiterpenes from Zanthoxylum rhoifolium Lam.

Zanthoxylum rhoifolium Lam. is a South American native tree belonging to the Rutaceae family, commonly known as Indian ash. It is mostly found in the eastern rainforest of the Atlantic coast, in the states of Minas Gerais and Rio de Janeiro, and in the North-East in the states of Piauí and Ceará [1]. The plant is traditionally employed in medicine for inflammatory, microbial and malaria processes and, to be specific, the roots are used as a febrifuge, gastroprotector and tonic, while the barks are used to treat flatulence, colic, dyspepsia and for their antinociceptive activity [2-3]. In previous phytochemical studies carried out on the bark, leaves, and fruits extracts of the plant, alkaloids, coumarins, lignans, terpenes, and flavonoids have been isolated [4-7]. Furthermore, the CHCl3-MeOH extract, obtained from the plant bark showed in our previous preliminary work fungistatic effect on Botrytis cinerea, Sclerotinia sclerotiorum, Alternaria alternata, Colletotrichum gloeosporioides, and Clonostachys rosea [8]. In the present study, leaves and barks separately were subjected to static maceration using solvents of increasing polarity, petroleum ether, CHCl3, CHCl3-MeOH (9:1), and MeOH, and after comparing the chromatographic profiles of the extracts with UHPLC-ESI-HR-Orbitrap/MS, the apolar and medium polarity extracts were considered for phytochemical investigation. The study of the extracts was conducted using different chromatographic techniques such as Sephadex LH-20, Biotage® flash chromatography, and RP-HPLC. The structural characterization of the obtained compounds was performed using 1D and 2D NMR and mass spectrometry. A variety of sesquiterpenes were isolated from the petroleum ether extract of the barks, four of which were never previously isolated, while several alkaloids and some flavonoids were isolated from the CHCl3-MeOH (9:1) extract. On the other hand, additional and different specialized metabolites such as vitamin E, lignans, coumarins, sesquiterpenes, and alfa-ionones, including a newly reported structure, were isolated from the CHCl3 and CHCl3-MeOH (9:1) leaves extracts. Besides, the antimicrobial activity of all extracts and isolated compounds is currently under studies, considering their pharmacological properties reported in the literature.