Wei-Hua Jiao

Hippolachnin A, a New Antifungal Polyketide from the South China Sea Sponge Hippospongia lachne

Hippolachnin A (1), a polyketide possessing an unprecedented carbon skeleton with a four-membered ring, was isolated from the South China Sea sponge Hippospongia lachne. The structure was elucidated using MS and NMR spectroscopic analyses, and the absolute configuration was determined using a calculated ECD method. Hippolachnin A demonstrated potent antifungal activity against three pathogenic fungi, Cryptococcus neoformans, Trichophyton rubrum, and Microsporum gypseum, with a MIC value of 0.41 μM for each fungus.

Anti-inflammatory triterpenes from the leaves of Rosa laevigata.

Bioassay-guided fractionation of an EtOAc extract of the leaves of Rosa laevigata afforded two new 19-oxo-18,19-seco-ursane-type triterpenes (1 and 3), a new ursane-type nortriterpene (2), a new ursane-type triterpene lactone saponin (4), and two new oleanane-type triterpenoids (5 and 6), together with eight known triterpenoids (7-14). Compound 1, a 19-oxo-18,19-seco-28-norursane, possesses a conjugated diene between C-12 and C-17. Several of the isolated compounds (1, 5, 7, 11, and 13) exhibited moderate activities in anti-inflammatory assays in vitro.

Quassidines A−D, Bis-β-carboline Alkaloids from the Stems of Picrasma quassioides

Four new bis-beta-carboline alkaloids, quassidines A-D (1-4), together with a known alkaloid, picrasidine C (5), were isolated from the stems of Picrasma quassioides. Quassidine A (1) is the first reported bis-beta-carboline alkaloid possessing a novel cyclobutane moiety. The structures of the new compounds were determined on the basis of their 1D and 2D NMR and X-ray diffraction data. A possible biogenetic pathway for these alkaloids was proposed, and all compounds were evaluated for anti-inflammatory activity. Only quassidine A (1) showed weak activity.

Dysideanones A-C, unusual sesquiterpene quinones from the South China Sea sponge Dysidea avara.

Dysideanones A-C (1-3), three unusual sesquiterpene quinones with unprecedented carbon skeletons, were isolated from the South China Sea sponge Dysidea avara. Their structures including absolute configurations were determined by a combination of spectroscopic analyses and calculated ECD spectra. Within the sesquiterpene quinone structures, dysideanones A (1) and B (2) share an unprecedented 6/6/6/6-fused tetracyclic carbon skeleton, while dysideanone C (3) possesses an unusual 6/6/5/6-fused tetracyclic core. Dysideanone B (2) showed cytotoxicity against two human cancer cell lines, HeLa and HepG2, with IC50 values of 7.1 and 9.4 μM, respectively.

Reniochalistatins A-E, cyclic peptides from the marine sponge Reniochalina stalagmitis.

Five new cyclic peptides (including four heptapeptides and one octapeptide), reniochalistatins A-E (1-5), were isolated and characterized from the marine sponge Reniochalina stalagmitis collected off Yongxing Island in the South China Sea. Their structures were assigned on the basis of HRESIMS, 1D and 2D NMR spectroscopic data, and MALDI-TOF/TOF data for sequence analysis. The absolute configurations of all of the amino acid residues were determined using chiral-phase HPLC and Marfeys analysis. The cyclic octapeptide reniochalistatin E showed biological activity in various cytotoxicity assays employing different tumor cell lines (RPMI-8226, MGC-803, HL-60, HepG2, and HeLa).

Hippolides A-H, acyclic manoalide derivatives from the marine sponge Hippospongia lachne.

Eight new acyclic manoalide-related sesterterpenes, hippolides A-H (1-8), together with two known manoalide derivatives, (6E)-neomanoalide (9) and (6Z)-neomanoalide (10), were isolated from the South China Sea sponge Hippospongia lachne. The absolute configurations of 1-8 were established by the modified Moshers method and CD data. Compound 1 exhibited cytotoxicity against A549, HeLa, and HCT-116 cell lines with IC50 values of 5.22×10(-2), 4.80×10(-2), and 9.78 μM, respectively. Compound 1 also showed moderate PTP1B inhibitory activitiy with an IC50 value of 23.81 μM, and compound 2 showed moderate cytotoxicity against the HCT-116 cell line and PTP1B inhibitory activity with IC50 values of 35.13 and 39.67 μM, respectively. In addition, compounds 1 and 5 showed weak anti-inflammatory activity, with IC50 values of 61.97 and 40.35 μM for PKCγ and PKCα, respectively.

Simplextones A and B, Unusual Polyketides from the Marine Sponge Plakortis simplex

Two novel polyketides, simplextones A (1) and B (2), were isolated from the sponge Plakortis simplex. Their structures were established by spectroscopic methods. The absolute configurations were assigned by modified Moshers method, X-ray crystallographic analysis, and quantum mechanical calculation of the electronic circular dichroism (ECD) spectrum. Compounds 1 and 2 featured an unprecedented polyketide skeleton via the connection of a single carbon-carbon bond to form a cyclopentane. These compounds also exhibited moderate cytotoxicity.

(±)-Quassidines I and J, Two Pairs of Cytotoxic Bis-β-carboline Alkaloid Enantiomers from Picrasma quassioides

(±)-Quassidines I (1) and J (2), two pairs of new bis-β-carboline alkaloid enantiomers, were isolated from the stems of Picrasma quassioides. Their structures were determined by the analysis of spectroscopic data, including HRESIMS and 2D NMR, and confirmed by single-crystal X-ray diffraction analysis. The racemic mixtures of 1 and 2 were resolved into two pairs of enantiomers, (+)-S-1a and (-)-R-1b and (+)-S-2a and (-)-R-2b, by HPLC using a chiral Daicel IB-3 column, respectively, which represents the first successful example to resolve bis-β-carboline racemic mixtures. The absolute configurations of the two pairs of enantiomers were determined by comparison between the calculated and experimental ECD spectra. The cytotoxicity evaluation revealed that (+)-S-1a and (+)-S-2a showed more potent cytotoxicity against human cervical HeLa and gastric MKN-28 cancer cell lines with IC50 values of 4.03-6.30 μM than their enantiomers with IC50 values of 9.64-12.3 μM; however, the two (+)-S-quassidines showed similar activities to their enantiomers against the mouse melanoma B-16 cancer cell line.

Dysiherbols A-C and Dysideanone E, Cytotoxic and NF-κB Inhibitory Tetracyclic Meroterpenes from a Dysidea sp. Marine Sponge.

Four new tetracyclic meroterpnes, dysiherbols A-C (1-3) and dysideanone E (4), were isolated from a Dysidea sp. marine sponge collected from the South China Sea. Their complete structures and absolute configurations were unambiguously determined by a combination of NMR spectroscopic data, ECD calculations, and single-crystal X-ray diffraction analysis. Within the sesquiterpene quinol structures, dysiherbols A-C possess an intriguing 6/6/5/6-fused tetracyclic carbon skeleton. The NF-κB inhibitory and cytotoxic activity evaluation disclosed that dysiherbol A (1) showed potent activity with respective IC50 values of 0.49 and 0.58 μM, which were about 10-fold and 20-fold more potent than those of dysiherbols B (2) and C (3), which feature hydroxy and ketone carbonyl groups at the C-3 position.

Cytotoxic aaptamine derivatives from the South China Sea sponge Aaptos aaptos.

Nine new aaptamine derivatives (1-9), together with three known related compounds (10-12), have been isolated from the South China Sea sponge Aaptos aaptos. The structures of all compounds were unambiguously elucidated on the basis of spectroscopic analyses. Structurally, compound 1 possesses a piperidinyl group fused to a demethyl(oxy)aaptamine moiety, whereas compounds 3-6 share an imidazole-fused 1H-benzo[de][1,6]naphthyridin-2(4H)-one skeleton. The cytotoxic activities of the compounds were evaluated against various human cancer cell lines, and compounds 2, 8, 11, and 12 showed potent cytotoxicities against HL60, K562, MCF-7, KB, HepG2, and HT-29 cells, with IC50 values in the range of 0.03 to 8.5 μM.