To study the nutritional composition of Indian Moringa oleifera seed and the antioxidant activity of M. oleifera seed polypeptide, Indian M. oleifera seed was used as raw material for composition analysis and content determination. After extraction of the seed protein, enzymatic hydrolysis with flavourzyme, dispase, papain, pepsin, and alcalase was conducted for different time, and the optimal enzymatic hydrolysis conditions was determined with DPPH scavenging capacity as an indicator. The seed polypeptides obtained by enzymatic hydrolysis were ultrafiltered, and the active peptide fragments were tracked with DPPH, HO (•OH), ABTS and superoxide anion (O₂•⁻) free radical scavenging ability and lipid oxidation inhibition rate as indicators. The results showed that the protein content in Indian M. oleifera seed was high to 40.34%, containing seven essential amino acids. The content of macroelements such as potassium, sodium, and magnesium is high, with the potassium content as high as 2,357.71 mg/kg, among the microelements, the iron content as high as 36.2 mg/kg. The optimum enzymatic hydrolysis conditions were as follows: enzymatic hydrolysis with flavourzyme (50°C, pH 6.7) for 300 min, and DPPH scavenging capacity was 84.76%. Activity tracing found that the polypeptide fragment with molecular weight <3.5 kDa had the strongest antioxidant capacity, and the EC₅₀ values of DPPH, •OH, ABTS, and O₂•⁻ free radical scavenging rates were 4.0, 4.2, 5.3, and 4.3 mg/ml, respectively. The above results show that Indian M. oleifera seed not only has high nutritional value, but its protease enzymatic hydrolyzate also has significant antioxidant activity, which can be further developed into nutrition products, healthcare products, functional foods, beauty and skin care products, liver protection drugs, etc.

Two new indole-diterpenoids (1 and 2) and a new isocoumarin (3), along with the known β-aflatrem (4), paspalinine (5), leporin B (6), α-cyclopiazonic acid (7), iso-α-cyclopiazonic acid (8), ditryptophenaline (9), aflatoxin B₁ (10), 7-O-acetylkojic acid (11) and kojic acid (12), were isolated from the fermentation broth of the marine-derived fungus, Aspergillus flavus OUCMDZ-2205. The structures of Compounds 1–12 were elucidated by spectroscopic analyses, quantum ECD calculations and the chemical method. New Compound 1 exhibited antibacterial activity against Staphylococcus aureus with a MIC value of 20.5 μM. Both new Compounds 1 and 2 could arrest the A549 cell cycle in the S phase at a concentration of 10 μM. Compound 1 showed PKC-beta inhibition with an IC₅₀ value of 15.6 μM. In addition, the absolute configurations of the known compounds, 4–6 and leporin A (6a), were also determined for the first time.

To obtain structurally novel and bioactive natural compounds from marine-derived microorganisms, the effect of high salt stress on secondary metabolite production in the marine-derived fungal strain, Spicaria elegans KLA-03, was investigated. The organism, which was isolated from marine sediment, produced different secondary metabolites when cultured in 3% and 10% saline conditions. Four characteristic metabolites, only produced in the 10% salinity culture, were isolated, and their structures were identified as (2E,2'Z)-3,3'-(6,6'-dihydroxybiphenyl-3,3'-diyl)diacrylic acid (1), aspulvinone E (2), aspochalasin E (3) and trichodermamide B (6), according to their 1D and 2D NMR spectra. Compound 1 is a new compound. High salt stress may therefore be a promising means to induce the production of new and chlorinated compounds in halotolerant fungi. Compound 1 showed moderate antibacterial activity against Pseudomonas aeruginosa and Escherichia coli with minimum inhibitory concentration (MIC) values of 0.038 and 0.767 mM, respectively.

A chemical-epigenetic method was used to enhance the chemodiversity of a marine algicolous fungus. Apart from thirteen known compounds, (+)-brevianamide R ((+)-3), (‒)-brevianamide R ((‒)-3), (+)-brevianamide Q ((+)-4), (‒)-brevianamide Q ((‒)-4), brevianamide V ((+)-5), brevianamide W ((‒)-5), brevianamide K (6), diorcinol B (7), diorcinol C (8), diorcinol E (9), diorcinol J (10), diorcinol (11), 4-methoxycarbonyldiorcinol (12), two new compounds, (+)- and (‒)-brevianamide X ((+)- and (‒)- 2)), as well as a new naturally occurring one, 3-[6-(2-methylpropyl)-2-oxo-1H-pyrazin-3-yl]propanamide (1), were isolated from chemical-epigenetic cultures of Aspergillus versicolor OUCMDZ-2738 with 10 µM vorinostat (SAHA). Compared to cultures in the same medium without SAHA, compounds 1–4, 8, 9, 11, and 12 were solely observed under SAHA condition. The structures of these compounds were elucidated based on spectroscopic analysis, specific rotation analysis, ECD, and X-ray crystallographic analysis. (±)-3, (±)-4, and (±)-5 were further resolved into the corresponding optically pure enantiomers and their absolute configurations were determined for the first time. Compounds 11 and 12 showed selective antibacterial against Pseudomonas aeruginosa with a minimum inhibitory concentration (MIC) of 17.4 and 13.9 μM, respectively. Compound 10 exhibited better α-glucosidase inhibitory activity than the assay control acarbose with IC₅₀ values of 117.3 and 255.3 μM, respectively.

Graphical The mechanisms of antioxidant peptides EP4 and EP5 on protecting HUVECs from oxidative damage.