Ziziphus joazeiro Mart., popularly known as “juazeiro”, is a tree widely found in the northeast of Brazil. It is commonly used as an anti-inflammatory, antibacterial, antifungal, and analgesic agent. The stem extract exhibited, beside cytotoxic properties, substantial activity against the Gram-negative bacterium Allivibrio fischeri. UHPLC-ESI-Orbitrap-HR-MS analysis of the alkaloidal fraction of the crude methanolic stem extract of this species enabled the detection and putative identification of sixteen cyclopeptide alkaloids (CPAs), including four possibly new structures. According to the MS2 fragmentation analysis, from the sixteen identified CPAs, three possess a type-Ia1, one a type-Ia2, and twelve a type-Ib cyclopeptide alkaloid core. The structures of paliurine-C and -D were supported by NMR data.

In the last decade thiotaurine, 2-aminoethane thiosulfonate, has been investigated as an inflammatory modulating agent as a result of its ability to release hydrogen sulfide (H2S) known to play regulatory roles in inflammation. Thiotaurine can be included in the “taurine family” due to structural similarity to taurine and hypotaurine, and is characterized by the presence of a sulfane sulfur moiety. Thiotaurine can be produced by different pathways, such as the spontaneous transsulfuration between thiocysteine – a persulfide analogue of cysteine – and hypotaurine as well as in vivo from cystine. Moreover, the enzymatic oxidation of cysteamine to hypotaurine and thiotaurine in the presence of inorganic sulfur can occur in animal tissues and last but not least thiotaurine can be generated by the transfer of sulfur from mercaptopyruvate to hypotaurine catalyzed by a sulfurtransferase. Thiotaurine is an effective antioxidant agent as demonstrated by its ability to counteract the damage caused by pro-oxidants in the rat. Recently, we observed the influence of thiotaurine on human neutrophils functional responses. In particular, thiotaurine has been found to prevent human neutrophil spontaneous apoptosis suggesting an alternative or additional role to its antioxidant activity. It is likely that the sulfane sulfur of thiotaurine may modulate neutrophil activation via persulfidation of target proteins. In conclusion, thiotaurine can represent a biologically relevant sulfur donor acting as a biological intermediate in the transport, storage and release of sulfide.

Chirita drakei Burtt (now accepted as Primulina drakei (B.L.Burtt) Mich.Möller & A.Weber) is growing on limestone mountain slopes of Ha Long Bay islands in Vietnam. The chemical investigation of the aerial parts of C. drakei led to the isolation and structural elucidation of two new compounds named chiridrakoside A (1) and chiridrakoside B (2) besides twelve known compounds comprising five phenylethanoid glycosides (3–7), two lignans (8, 9), a phenyl propanoid (10), an anthraquinone (11), a furan derivative (12) and two triterpenes (13, 14). All described compounds, except 4, 5 and 11, were obtained for the first time from the genera Chirita or Primulina. The cytotoxic activity of the isolated compounds was evaluated against the four human cancer cell lines KB (mouth epidermal carcinoma), HepG2 (hepatocellular carcinoma), Lu (lung carcinoma) and MCF7 (breast carcinoma). Epoxyconiferyl alcohol (10) exhibited cytotoxic activity against the tested cell lines (IC50 from 46 to 128 μM).

Rothmannia talbotii, a hitherto chemically unexplored medicinal plant, is used in the Western Region of Cameroon to relieve fever. In our ongoing search for bioactive compounds from Cameroonian medicinal plants, a previously undescribed compound rothtalazepane (1), along with six known compounds, aitchisonide B (2), D-mannitol (3), β-D-glucopyranosyl-(6→1’)-β-D-glucopyranoside (4), monopalmitin (5), stigmasterol (6), and sitosterol 3-O-β-D-glucopyranoside (7) were isolated and characterized from the crude ethanol extract of the wood of R. talbotii. Rothtalazepane (1) exhibits no significant activity against several microbial strains, thus its function likely lies not in antimicrobial defense and it is not the active principle against urinary infections described for Rothmannia.

Four new 19-residue peptaibols, named tulasporins A–D (1–4), were isolated from the semi-solid cultures of Sepedonium tulasneanum. Their structures were elucidated on the basis of extensive ESI-HRMSn fragmentation studies as well as 1H NMR spectroscopic analyses. Interestingly, the structures of tulasporins A–D (1–4) resemble those of chrysospermins isolated earlier from cultures of S. chrysospermum. Previously, it was hypothesized that the peptaibol production by Sepedonium species correlates with the morphology of the aleurioconidia, as exclusively round-shaped aleurioconidia forming species produced peptaibols. Since the investigated Sepedonium tulasneanum produces oval aleurioconidia, this study can be considered as the first report of peptaibols from a Sepedonium strain with oval-shaped aleurioconidia. Thus, it could be demonstrated that both round as well as oval aleurioconidia forming Sepedonium species are able to produce peptaibols. Tulasporins A-D (1–4), when tested against phytopathogenic fungi, exhibited good growth inhibitory activity against both Botrytis cinerea and Phytophthora infestans, while they were devoid of significant activity against Septoria tritici.

Two new fungal pigments named schweinitzins A and B (1-2), together with (S)-torosachrysone-8-O-methyl ether (3) and emodin-6,8-di-O-methyl ether (4) have been isolated from the methanolic extract of the fruit bodies of Xylaria schweinitzii (Xylariaceae) collected in Cuc Phuong national park, Ninh Binh province, Vietnam, by silica gel column chromatography and preparative HPLC. Their structures were elucidated by spectroscopic analysis such as IR, UV-Vis, 2D NMR and FT-ICR-MS. In addition, two compounds (1 and 3) showed strong cytotoxicity against all four cancer cell lines, KB (a human epidermal carcinoma), MCF7 (human breast carcinoma), SK-LU-1 (human lung carcinoma) and HepG2 (hepatocellular carcinoma).

The essential oil from the leaves of Tagetes minuta L., growing wild in Yemen, was obtained by hydrodistillation and analyzed by gas chromatography-mass spectrometry. A total of 28 compounds were identified representing 74.2% of total oil composition. Major components of the essential oil were (Z)-ocimenone (15.9%), (E)-ocimenone (34.8%), (Z)-β-ocimene (8.3%), limonene (2.3%), (Z)-tagetone (1.8%), dihydrotagetone (1.4%) and an unidentified dimethylvinylketone derivative (20.6%). The oil showed moderate cytotoxic activity against MCF-7 breast tumor cells, with an IC50 of 54.7 ± 6.2 μg/mL. In the DPPH radical scavenging assay, T. minuta oil showed potent antiradical activity with an IC50 value of 36 μg/mL. Antimicrobial activity was also investigated on several microorganisms, and the essential oil exhibited high activity against methicillin-resistant Staphylococcus aureus (MRSA) with an inhibition zone of 23 mm. It also exhibited remarkable antifungal activity against Candida albicans with an inhibition zone of 26 mm.

The leaf essential oil of Tarchonanthuscamphoratus(Asteraceae) was obtained by hydrodistillation and analyzed by GC-MS. Fifty-six components were characterized, representing 94.2% of the total oil with oxygenated monoterpenes (48.3%) and oxygenated sesquiterpenes (32.7%) as the major groups. The principal constituents were identified as endo-fenchol (21.2%), trans-pinene hydrate (8.8%), caryophyllene oxide (7.5%), α-terpineol (6.4%), τ-cadinol (6.4%), and α-cadinol (5.2%). The essential oil was evaluated for its antimicrobial activity using a disc diffusion assay resulting in the moderate inhibition of a number of common human pathogenic bacteria, including methicillin-resistant Staphylococcus aureus(MRSA) and the yeast Candida albicans. The inhibition zones varied from 10 to 14mm/disc. Furthermore, the antioxidant capacity of the essential oil was examined using an in vitroradical scavenging activity test. The T. camphoratus essential oil scavenged 1,1-diphenyl-2-picrylhydrazyl radical (DPPH), resulting in an IC50value of 5.6 mg/mL. At concentrations of 100 and 50μg/mL, the oil showed cytotoxic activity, with growth inhibition of 59.1% (±4.2), and 16.2% (±8.7) against HT29 tumor cells (human colonic adenocarcinoma cells), respectively(IC50 = 84.7 ± 7.5 μg/mL).

The chemical composition of the hydrodistilled leaf essential oil from Pulicaria stephanocarpa Balf Fil was determined by GC-MS analysis, and its antimicrobial, antioxidant and anticholinesterase (AChE) activities were evaluated. Eighty-three compounds were identified representing 97.2% of the total oil. (E)-Caryophyllene 13.4%, (E)-nerolidol 8.5%, caryophyllene oxide 8.5%, α-cadinol 8.2% spathulenol 6.8% and τ-cadinol 4.7%, were the main components. Antimicrobial activity of the oil, evaluated using the disc diffusion and broth dilution methods, demonstrated the highest susceptibility on Gram-positive bacteria and Candida albicans. The free radical scavenging ability of the oil was assessed by the DPPH assay to show antiradical activity with IC50 of 330 μg/mL. Moreover, the oil revealed an AChE inhibitory activity of 47% at a concentration of 200 μg/mL using Ellman's method.

The chemical composition, antimicrobial, antioxidant and cytotoxic activities of the essential oils isolated from the leaves of Plectranthus cylindraceus Hoechst. ex. Benth. (EOPC) and Meriandra benghalensis (Roxb.) Benth. (EOMB) were investigated. Sixteen compounds were identified in P. cylindraceus oil representing 94.5% of the oil content with thymol (68.5%), terpinolene (5.3%), β-selinene (4.7%), β-caryophyllene (4.0%), δ-cadinol (2.1%), and ar-curcumene (1.7%) as the major compounds. In M. benghalensis oil, 12 compounds were identified, which made up 82.0% of the total oil. The most abundant constituents were camphor (43.6%), 1,8-cineole (10.7%), α-eudesmol (5.8%), caryophyllene oxide (5.8%), camphene (5.3%) and borneol (3.4%). The antimicrobial activities of both oils were evaluated against five microorganisms with the disc diffusion test, the broth micro-dilution method and a semiquantitative bioautographic test. The most sensitive microorganisms for P. cylindraceus oil were S. aureus, B. subtilis, and C. albicans with inhibition zones of 38, 42, and 43 mm and MIC values of 0.39, 0.18, and, 0.18 μL/mL, respectively. M. benghalensis oil showed weak to moderate activity against the tested microorganisms. 2,2-Diphenyl-1-picrylhydrazyl (DPPH) assay was employed to study the potential antioxidant activities of both oils. The antioxidant activity of P. cylindraceus oil (IC50 34.5 μg/mL) appeared to be higher than that of M. benghalensis oil (IC50 935 μg/mL). At a concentration of 100 μg/mL, EOMB showed a stronger cytotoxic activity, with growth inhibition of 71% against HT29 tumor cells, than EOPC (18%).