https://pubs.rsc.org/en/content/articlepdf/2019/NP/C8NP00092A

Marine natural products.

Covering: 2010. Previous review: Nat. Prod. Rep., 2011, 28, 196. This review covers the literature published in 2010 for marine natural products, with 895 citations (590 for the period January to December 2010) referring to compounds isolated from marine microorganisms and phytoplankton, green, brown and red algae, sponges, cnidarians, bryozoans, molluscs, tunicates, echinoderms, mangroves and other intertidal plants and microorganisms. The emphasis is on new compounds (1003 for 2010), together with the relevant biological activities, source organisms and country of origin. Biosynthetic studies, first syntheses, and syntheses that lead to the revision of structures or stereochemistries, have been included.

Review: Marine natural products

The potential of mangrove-derived endophytic fungi as a promising source of diverse and structurally unprecedented bioactive natural products is unquestionable and continues to attract considerable attention. This review highlights new bioactive mangrove fungal metabolites and known compounds with hitherto unreported biological activities described during the last 10 years. The compounds are categorized according to their reported biological activities, including cytotoxic, anti-infective, in addition to a wide range of miscellaneous activities such as protein kinase, α-glucosidase, acetylcholinesterase and tyrosinase inhibitory activities, as well as antiangiogenic and neovascularisation effects, radical scavenging, DNA-binding affinity, and calcium and potassium channel blocking activity.

Mangrove derived fungal endophytes – a chemical and biological perception

This review summarizes new findings concerning the sources and characteristics of various natural products that can be extracted from mangrove-associated microbes over the past three years (January 2011–December 2013). The natural products are discussed with a focus on bioactivity, highlighting the unique chemical diversity of these metabolic products.

Bioactive natural products derived from mangrove-associated microbes

The skin is chronically exposed to endogenous and environmental pro-oxidant agents, leading to the harmful generation of reactive oxygen species. Antioxidant is vital substances which possess the ability to protect the body from damage cause by free radicals induce oxidative stress. Alpinia zerumbet, a traditionally important economic plant in Okinawa, contains several interesting bioactive constituents and possesses health promoting properties. In this regard, we carried out to test the inhibitory effect of crude extracts and isolated compounds from A. zerumbet on antioxidant and skin diseases-related enzymes. The antioxidant activities were examined by DPPH, ABTS and PMS-NADH radical scavenging. Collagenase, elastase, hyaluronidase and tyrosinase were designed for enzymatic activities to investigate the inhibitory properties of test samples using a continuous spectrophotometric assay. The inhibitory capacity of test samples was presented at half maximal inhibitory concentration (IC50). The results showed that aqueous extract of the rhizome was found to have greater inhibitory effects than the others on both of antioxidant and skin diseases-related enzymes. Furthermore, 5,6-dehydrokawain (DK), dihydro-5,6-dehydrokawain (DDK) and 8(17),12-labdadiene-15,16-dial (labdadiene), isolated from rhizome, were tested for antioxidant and enzyme inhibitions. We found that DK showed higher inhibitory activities on DPPH, ABTS and PMS-NADH scavenging (IC50 = 122.14 ± 1.40, 110.08 ± 3.34 and 127.78 ± 4.75 μg/ml, respectively). It also had stronger inhibitory activities against collagenase, elastase, hyaluronidase and tyrosinase (IC50 = 24.93 ± 0.97, 19.41 ± 0.61, 19.48 ± 0.24 and 76.67 ± 0.50 μg/ml, respectively) than DDK and labdadiene. Our results indicate that the rhizome aqueous extract proved to be the source of bioactive compounds against enzymes responsible for causing skin diseases. Moreover, DK could be used as a potent inhibitor and be further exploited to be used in anti-skin disease formulations.

/pdf/effect-of-alpinia-zerumbet-components-on-antioxidant-and-54gc8pa4t4.pdf

Effect of Alpinia zerumbet components on antioxidant and skin diseases-related enzymes

Broussonetia papyrifera leaves (BPL) as a traditional Chinese medicine are also used in livestock feed for stimulating reproduction, adipose tissue and muscle development; however, the mechanism of their action is still unknown. Through estrogen biosynthesis-guided fractionation in human ovarian granulosa-like KGN cells, five new phenolic glycosides, broussoside A–E(1–5), along with fifteen known dietary phenolic compounds, were isolated from the n-butanol extract of BPL, and their structures were elucidated on the basis of NMR spectra analysis and chemical evidence. New compounds 3, 4, 5 and the known compounds 9 and 10 were found to potently inhibit estrogen biosynthesis in KGN cells. In addition, compounds 9, 17, 18, and 20 showed strong antioxidant activity against ABTS (2,2′-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) diammonium salt) and DPPH (1, 1′-diphenyl -2-picryl-hydrazyl radical) assays. These findings suggest that BPL may improve meat quality through the regulation of estrogen biosynthesis. Furthermore, they may be useful for the discovery of potential aromatase modulators from natural products. Finally, they could be considered as a new source for natural antioxidants.

/pdf/isolation-and-characterization-of-new-phenolic-compounds-fl3phrg6en.pdf

Isolation and Characterization of New Phenolic Compounds with Estrogen Biosynthesis-Inhibiting and Antioxidation Activities from Broussonetia papyrifera Leaves

Six new pentacyclic triterpenoid saponins, centelloside F (1), centelloside G (2), 11-oxo-asiaticoside B (3), 11-oxo-madecassoside (4), 11(β)-methoxy asiaticoside B (5), and 11(β)-methoxy madecassoside (6), along with seven known ones, asiaticoside (7), asiaticoside B (8), madecassoside (9), centellasaponin A (10), isoasiaticoside (11), scheffoleoside A (12), and centelloside E (13), were separated from the 80% MeOH extract of the whole plant of Centella asiatica, which has been used as a medicinal plant and is now commercially available as a diatery supplement in many countries. Compounds 1 and 2, 3 and 4, and 5 and 6 are three pairs of isomers with oleanane- or ursane-type triterpenes as aglycones. The chemical structures of the new triterpene saponins were fully characterized by extensive analysis of their nuclear magnetic resonance and high-resolution electrospray ionization mass spectrometry data. The protective effects of compounds 1-13 on PC12 cells induced by 6-OHDA were screened, and compound 3 displayed the best neuroprotective effect, with 91.75% cell viability at the concentration of 100 μM. Moreover, compound 3 also attenuated cell apoptosis and increased the mRNA expression of antioxidant enzymes, including superoxide dismutase and catalase. Additionally, compound 3 activated the phosphatidylinositol 3-kinase/Akt pathway, including PDK1, Akt, and GSK-3β. These findings suggested that triterpene saponins from C. asiatica were worthy of further biological research to develop new neuroprotective agents.

Oleanane- and Ursane-Type Triterpene Saponins from Centella asiatica Exhibit Neuroprotective Effects.

!Two newlactones, 1 and 2, together with fiveknown compounds, 3–7, were isolated from the marine mangrove fungus Xylaria sp. BL321. Their structures were determined by comprehensive analysis of their MS and NMR spectroscopic data. The absolute configurations of 1 and 2 were established on the basis of electronic circular dichroism calculations. It was found that the exocyclic double bond of 1 rearranged into a cyclic double bond to form a new crystal compound (1a) in diluted NaOH solution. Compound 3 was isolated for the first time as a natural product; its absolute configurationwas determined by single-crystal X‑ray crystallography. Compounds 4–7 displayed cytotoxicity against human breast cancer cell lines MCF-7 and MDA‑MB‑435, while compounds 1–3 were inactive (IC50 > 50µM).

Bin Chen

Papers

Isolation and Characterization of New Phenolic Compounds with Estrogen Biosynthesis-Inhibiting and Antioxidation Activities from Broussonetia papyrifera Leaves

Oleanane- and Ursane-Type Triterpene Saponins from Centella asiatica Exhibit Neuroprotective Effects.

Metabolites of the mangrove fungus Xylaria sp. BL321 from the South China Sea.

Cucurbitane glycosides from the fruit of Siraitia grosvenori and their effects on glucose uptake in human HepG2 cells in vitro.

Two new alkaloids from Miliusa cuneata