The new triterpene friedelan-1,3,21-trione, the known compounds friedelan-3-one, 3β-friedelinol, 3,4-seco-friedelan-3-oic acid, 28-hydroxyfriedelan-3-one, friedelan-3-oxo-28-al, friedelan-3,21-dione, 30-hydroxyfriedelan-3-one, a mixture of 30-hydroxyfriedelan-3-one/21α-hydroxyfriedelan-3-one, 21β-hydroxyfriedelan-3-one, gutta-percha, squalene, and a mixture of palmitic/stearic/oleic acids were isolated from the hexane extracts of leaves and branches of T. micrantha. Their chemical structures were established by Fourier transform infrared spectroscopy (FTIR), gas chromatography (GC), 1D/2D nuclear magnetic resonance (NMR) and comparison with the literature data. All compounds were described for T. micrantha and the genus Tontelea for the first time. The branch and leaf extracts displayed anti-Zika virus activity at the lowest tested concentration of 15.6 µg mL-1, mainly virucidal effect, and presented no cytotoxicity to Vero cells. Furthermore, the ethyl acetate and methanolic leaf extracts demonstrated the best activities at the concentration of 31.2 and 15.6 µg mL-1 at the viral adsorption and penetration stages, respectively. These results showed that these extracts may be promising candidates for the Zika virus treatment.

ABSTRACT Studies on native medicinal plants strengthen initiatives to preserve the environments where those species naturally occur, many of them already strongly menaced even before their potential to humankind is known. Root and stem barks, leaves, and pericarps samples of Solanum agrarium Sendtn., S. lycocarpum A. St.-Hil., S. palinacanthum Dunal, S. paniculatum L., and S. stipulaceum Roem. & Schult., species that occur in the Cerrado (Brazililan savanna) were processed according to common light microscopy techniques for structural analysis, and histochemical tests were performed to locate and identify classes of chemical compounds. The distinctive features identified were low concentration of crystal sand in the root and stem, presence of terpene resin in the root, and absence of hypodermis in the leaf, in S. agrarium; bright spots (group of sclereids) in the root, isobilateral mesophyll, thickened cell walls with hemicelluloses and strong aroma in the fruit, in S. lycocarpum; high concentration of crystal sand in the root and stem, oval-shaped limb, presence of isolated crystals in the exocarp, in S. palinacanthum; strong sclerification and rays with great height in the root and stem, in S. paniculatum; and accumulation of soluble protein in the root and stem, presence of conspicuous membranaceous stipules, absence of spiniform trichomes, in S. stipulaceum. This work identifies distinctive structural features, its ecological importance, and determines the distribution of secondary compounds associated with the medicinal properties reported for these species and contributes to the conservation of the natural environments where they occur.

The composition of essential oils from flowers of Solanum stipulaceum Roem & Schult collected in May and September was studied for the first time. Effects of g-radiation on volatile constituents were investigated by gas chromatography (GC) with flame ionization detector (FID). In addition, the antileukemic activity was studied by a 3-(4,5-dimethylthiazol-2-yl)-2,5- diphenyltetrazolium bromide (MTT) colorimetric assay against human cell lines HL-60 and THP-1. The main constituents of the essential oil of flowers collected in May were β-caryophyllene (25.8%), γ-gurjunene (11.9%), and β-gurjunene (8.2%), whereas the essential oil of flowers collected in September was mainly composed of β-caryophyllene (26.5%), caryophyllene oxide (11.0%), and γ-gurjunene (10.0%). The main components of essential oil from flowers collected in September were not significantly affected by γ-radiation at lower doses than 10.0 kGy. No cytotoxic activity in leukemic cell lines was observed for non-irradiated samples. However, irradiated samples exhibited slightly cytotoxic activity.

The phytochemical study of hexane extract from leaves of Salacia crassifolia resulted in the isolation of 3β-palmitoxy-urs-12-ene, 3-oxofriedelane, 3β-hydroxyfriedelane, 3-oxo-28-hydroxyfriedelane, 3-oxo-29-hydroxyfriedelane, 28,29-dihydroxyfriedelan-3-one, 3,4-seco-friedelan-3-oic acid, 3β-hydroxy-olean-9(11):12-diene and the mixture of α-amirin and β-amirin. β-sitosterol, the polymer gutta-percha, squalene and eicosanoic acid were also isolated. The chemical structures of these constituents were established by IR, 1H and 13C NMR spectral data. Crude extracts and the triterpenes were tested against Entamoeba histolytica, Giardia lamblia and Trichomonas vaginalis and no activity was observed under the in vitro assay conditions. The hexane, chloroform, ethyl acetate and ethanol crude extracts, and the constituent 3,4-seco-friedelan-3-oic acid and 28,29-dihydroxyfriedelan-3-one showed in vitro antimicrobial activity against Salmonella typhimurium, Escherichia coli, Pseudomonas aeruginosa, Staphylococcus aureus, Bacillus cereus, Listeria monocytogenes, Streptococcus sanguinis and Candida albicans.