Twenty four sesquiterpenoids, 1–24, including 11 new sesquiterpenoids, jambolanins A–K, and two new norsesquiterpenoids, jambolanes A and B, along with six known triterpenoids, were isolated from the seeds of Eugenia jambolana fruit. Their structures were elucidated on the basis of NMR and MS spectrometry data analysis. Among the isolates, compound 13 possessed a rare 6,7-seco-guaiene skeleton, and compounds 14 and 15 were norsesquiterpenoids containing a spiro[4.4]nonane skeleton. Antimicrobial assay evaluation revealed that sesquiterpenoids, 4, 5/6, 17, 19, 21, 23, and 24 inhibited the growth of the Gram-positive bacterium, Staphylococcus aureus. The current study advances scientific knowledge of E. jambolana phytochemicals and suggests that its sesquiterpenoids may contribute, in part, to the anti-infective effects attributed to the edible fruit of this plant.Keywords: antimicrobial activity; Eugenia jambolana; Myrtaceace; sesquiterpenoids;

Fifteen new phloroglucinol derivatives, jamunones A–O (1–8 and 10–16, respectively), along with one known analogue spiralisone C (9), were isolated from Eugenia jambolana seeds. Their structures were elucidated by detailed nuclear magnetic resonance and mass spectrometry spectroscopic data interpretation. Compounds 1–9, 11, 12, and 14–16 inhibited protein tyrosine phosphatase 1B activity with IC50 values ranging from 0.42 to 3.2 μM.

Six new fusicoccane-type diterpenoids (2–7) were isolated from the fermentation broth of Streptomyces violascens, which was isolated from Ailuropoda melanoleuca (giant panda) feces. The structures of these new compounds were elucidated by a detailed spectroscopic data and X-ray crystallographic analysis. Compounds 5–7 demonstrated cytotoxicity against five human cancer cell lines, with IC50 values ranging from 3.5 ± 0.7 to 14.1 ± 0.8 μM. Cell adhesion, migration, and invasion assays showed that 6 inhibited the migration and invasion of human hepatocellular carcinoma SMMC7721 cells in a dose-dependent manner. Through further investigation, it was revealed that 6 inhibited the enzymatic activity of matrix metalloproteinase-2 (MMP-2) and matrix metalloproteinase-9 (MMP-9), in addition to down-regulating the expressions of MMP-2 and MMP-9 at both the protein and mRNA levels to influence the migration and invasion of cancer cells.

•Triterpenoid-enriched Jamun fruit extracts (TJFE) reduce hyperglycaemia.•TJFE enhance mouse glucose tolerance.•TJFE inhibit hepatic gluconeogenesis in mice.•TJFE improve Akt phosphorylation and Glut4 protein levels in skeletal muscle.•TJFE suppress the gluconeogenic gene expression of Pgc1α, Pepck, and G6Pase.In our investigation of the anti-hyperglycaemic constituents of Eugenia jambolana L. (Jamun), one new triterpenoid, 2-O-cis-p-coumaroyl maslinic acid, along with thirteen known triterpenoids were isolated from the fruit ethyl acetate extract. The structures of compounds 1–14 were elucidated on the basis of mass spectrometry and nuclear magnetic resonance analyses. Animal studies demonstrated that the triterpenoid-enriched Jamun fruit extract (TJFE) decreased blood glucose content in C57BL/6 mice (P < 0.05) upon sucrose loading challenge, improved the glucose tolerance in mice administrated with TJFE for 2 weeks via oral gavage (100 mg/kg body weight), and increased Akt phosphorylation levels and Glut4 protein levels in skeletal muscle. Additionally, TJFE administration inhibited hepatic gluconeogenesis through suppressing the gluconeogenic gene expression of Pgc1α, Pepck, and G6Pase. The current study advances scientific knowledge of Jamun constituents and suggests that triterpenoids may play an important role in the anti-diabetic properties attributed to this edible purple berry.

Hepatocellular carcinoma (HCC) is the most common type of liver cancer with high prevalence and mortality. Borrelidin, produced by several actinomycete bacteria of Streptomycin sp. exhibited diversiform activities including anti-bacterial, anti-viral, anti-angiogenic, and anti-tumor. However, the effect of borrelidin on HCC cells has not been characterized. The present study demonstrated borrelidin exhibited great potential to inhibit the growth of HCC cells, HepG2 and SMMC7721 in vitro. Western blot and real-time qPCR analysis revealed that borrelidin decreased the expressions of cyclin D1, cyclin D3, cyclin E1, CDK2, CDK4, and CDK6 and increased the expression of p21, thereby inducing G0/G1 cell cycle arrest. Moreover, borrelidin down-regulated expression of Bcl-2, up-regulated expression of Bax and increased cleavages of caspase-9 and caspase-3 to activate caspase-dependent apoptosis in HCC cells. Borrelidin inhibited migration and invasion through suppressing the expression of MMP-2 and MMP-9 in HCC cells. Further investigation indicated that the anti-tumor effect of borrelidin was mediated by MAPKs signaling pathway. In addition, an in vivo experiment revealed that borrelidin suppressed tumor growth in SMMC7721 xenograft model mice with few side effects. Cell cycle arrest and induced apoptosis were also observed in tumor tissues of model mice treated with borrelidin.

•Nineteen polyketides were isolated from Pestalotiopsis heterocornis.•Twelve previously undescribed compounds were characterized.•Nine compounds exhibited weak cytotoxicity.•Nine compounds showed antibacterial activities.•Four compounds indicated weak antifungal activities.Twelve previously undescribed polyketide derivatives, heterocornols A-L, and seven known analogues were isolated from a culture of the fungus Pestalotiopsis heterocornis associated with sponge. Their structures were elucidated by a comprehensive spectroscopic data analysis and CD Cotton effects. These compounds were evaluated for cytotoxic and antibacterial activities in vitro. Among them, heterocornols A-C, F-H, methyl-(2-formyl-3-hydroxyphenyl)propanoate, agropyrenol, and vaccinol G exhibited cytotoxicities against four human cancer cell lines with IC50 values 15–100 μM, and they also showed antibacterial activities against Gram-positive bacteria Staphylococcus aureus and Bacillus subtilis with MIC values ranging from 25 to 100 μg/mL. Moreover, compounds heterocornol C, heterocornol G, agropyrenol, and vaccinol G showed weak antifungal activities against Candida parapsilosis and Cryptococcus neoformans with MIC values 100 μg/mL.Download high-res image (150KB)Download full-size image

From a fermentation broth of Streptomyces albolongus obtained from Elephas maximus feces, nine bafilomycins (1–9) and seven odoriferous sesquiterpenoids (10–16) were isolated. The structures of the new compounds, including three bafilomycins, 19-methoxybafilomycin C1 amide (1), 21-deoxybafilomycin A1 (2), and 21-deoxybafilomycin A2 (3), and two sesquiterpenoid degradation products, (1β,4β,4aβ,8aα)-4,8a-dimethyloctahydronaphthalene-1,4a(2H)-diol (10) and (1β,4β,4aβ,7α,8aα)-4,8a-dimethyloctahydronaphthalene-1,4a,7(2H)-triol (11), were elucidated by comprehensive spectroscopic data analysis. The cytotoxicity activity against four human cancer cell lines and antimicrobial activities against a panel of bacteria and fungi of all compounds isolated were evaluated. Compounds 1, 7, and 8 were cytotoxic, with IC50 values ranging from 0.54 to 5.02 μM. Compounds 2, 7, 8, and 10 showed strong antifungal activity against Candida parapsilosis, with MIC values of 3.13, 1.56, 1.56, and 3.13 μg/mL respectively.

•Twenty five terpenoids were isolated from the rhizome of Alisma orientale.•Four previously undescribed terpenoids were characterized.•Nine compounds exhibited weak to moderate cytotoxicity.•Eight compounds showed antibacterial activities against B. subtilis or S. aureus.•Four compounds presented inhibition against NO production.Sixteen triterpenoids and nine sesquiterpenoids were isolated from the rhizome of Alisma orientale. Structures of 16-oxo-11-anhydroalisol A 24-acetate, 13β,17β-epoxy-24,25,26,27-tetranor-alisol A 23-oic acid, 1αH,5αH-guaia-6-ene-4β,10β-diol, and alisguaiaone were elucidated by comprehensive spectroscopic data analysis. The cytotoxic, antibacterial, antifungal, anti-inflammatory, and α-glucosidase inhibitory activities of isolated terpenoids were evaluated. Triterpenoids alisol A, alisol A 24-acetate, 25-O-ethylalisol A, 11-deoxyalisol A, alisol E 24-acetate, alisol G, alisol B 23-acetate and sesquiterpenoids 1αH,5αH-guaia-6-ene-4β,10β-diol, 10-hydroxy-7,10-epoxysalvialane exhibited cytotoxicities against the three tested human cancer cell lines with IC50 values ranging from 11.5 ± 1.7 μM to 76.7 ± 1.4 μM. Triterpenoids alisol A, 25-O-ethylalisol A, 11-deoxyalisol A, alisol E 24-acetate, alisol G, and 25-anhydroalisol F showed antibacterial activities against the Gram-positive strains Bacillus subtilis and Staphylococcus aureus with MIC values of 12.5–100 μg/mL. Sesquiterpenoid 4β,10β-dihydroxy-1αH,5βH-guaia-6-ene exhibited antibacterial activity against B. subtilis with an MIC value of 50 μg/mL, and 10-hydroxy-7,10-epoxysalvialane exhibited activity against S. aureus with an MIC value of 100 μg/mL. Compounds 16-oxo-11-anhydroalisol A 24-acetate, alisol F, 25-anhydroalisol F, and alisguaiaone exhibited inhibitory effects on lipopolysaccharide-induced NO production in RAW 264.7 macrophage cells. None of the compounds showed obvious inhibitory activity against α-glucosidase.Sixteen triterpenoids and nine sesquiterpenoids were isolated from the rhizome of Alisma orientale. Four previously undescribed terpenoids among them were elucidated by comprehensive spectroscopic data analysis.

•Longan pericarp extracts reduce postprandial hyperglycaemia by inhibiting α-glucosidase in the gut lumen.•Longan pericarp extracts enhance mouse glucose tolerance with short-term oral administration.•Longan pericarp extracts enhance insulin sensitivity via increasing Irs-1, Pparγ and Glut4 gene expression.The chemical composition and anti-hyperglycaemic effects of polyphenol-enriched Longan pericarp extracts (LPE) were investigated in the present study. The phenolic profile of LPE was determined by HPLC-DAD/MS analysis. Nine phenolics were identified, and of these, three major components were quantified by LC-MS/MS. Anti-hyperglycaemic assays demonstrate that LPE (polyphenol content ca. 37.8 g gallic acid equivalents/100 g) inhibit α-glucosidase (IC50 = 11.68 ± 0.44 µg/mL) in vitro and decrease blood glucose content in mice (P < 0.05) upon sucrose challenge. In addition, LPE improves mouse glucose tolerance following 5 days of treatment by oral gavage (10 mg/kg body weight), which may be due to the increased gene expression associated with insulin signalling pathway, such as insulin receptor substrate-1, peroxisome proliferator-activated receptor γ and glucose transporter 4. Overall, our results suggest that LPE could impact carbohydrate metabolism and enhance insulin sensitivity and may serve as a potential anti-hyperglycaemic agent in diabetes care.

Seven new compounds, including five pyrrol-2-aldehyde derivatives, jiangrines A–E (1–5), one indolizine derivative, jiangrine F (7), and one glycolipid, jiangolide (8), along with a known compound, pyrrolezanthine (6), were isolated from the fermentation broth of Jiangella gansuensis, an actinobacterium assigned to a novel family, Jiangellaceae, and a novel order, Jiangellales. The structures were elucidated by detailed spectroscopic analysis and through chemical methods. Compounds 1, 2, 3/4, 5, 6, and 8 demonstrated inhibitory effects on lipopolysaccharide-induced NO production in RAW 264.7 macrophage cells, with IC50 values of 97.8, 60.7, 30.1, 54.9, 58.8, and 61.4 μM, respectively.