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Re-investigation of the MeOH extract of the seeds of Cucumis melo L. var. reticulatus (Cucurbitaceae) led to the isolation of a new chromone derivative (5,7- dihydroxy-2-[2-(3-methoxy-4-hydroxyphenyl)ethyl]chromone (5) and a triglyceride (1,3-di-(6Z,9Z)-docosa-6,9-dienoyl-2-(6Z) hexacos-6-enoylglycerol (1), together with three known compounds; alpha-spinasterol (2), stigmasta-7,22,25-trien-3-ol (3), and D:B-friedoolean-5-ene-3-beta-ol (4), are reported from this species for the first time. Their structures were determined by extensive 1D (1H, 13C, and DEPT) and 2D (1H-1H COSY, HMQC, and HMBC) NMR and mass spectral measurements. Compound 5 displayed significant cytotoxic activity against L5178Y cells, with an ED50 of 5 microM. The MeOH extract and 5 showed antioxidant activity using the DPPH assay.

Re-investigation of the methanolic extract of the sponge Diacarnus megaspinorhabdosa afforded one new norsesterpene cyclic peroxide diacarperoxide S (2), in addition to two known compounds sigmosceptrellin B (1) and nebularine (3). The structures of the isolated compounds were established on the basis of one and two dimensional NMR spectroscopic studies (1H, 13C, DEPT, COSY, HMQC, HMBC, and ROESY) as well as on mass spectral analysis. The isolated compounds were evaluated for their cytotoxic as well as antimicrobial activities.

Chemical investigation of the methanolic extract of the seeds of Cucumis melo L. var. reticulatus (Cucurbitaceae) afforded three new chromone derivatives; 5,7-dihydroxy-2-[2-(4-hydroxyphenyl)ethyl]chromone 3, 5,7-dihydroxy-2-[2-(3,4-dihydroxyphenyl)ethyl]chromone 4, and 7-glucosyloxy-5-hydroxy-2-[2-(4-hydroxyphenyl)ethyl]chromone 6, together with three known compounds; beta-amyrin 1, beta-sitosterol 2, and beta-sitosterol-3-O-beta-glucopyranoside 5. Their structures were established by UV, IR, 1D and 2D NMR, in addition to mass spectroscopic data and comparison with literature data. The n-hexane and methanolic extracts were evaluated for their antimicrobial activity, as well as cytotoxic activity using the brine shrimp bioassay.