Limonoids from the Branches and Leaves of Aglaia lawii and Their Cytotoxic Activities

Three undescribed limonoids (1-3), named aglaians G-I, and one new natural product azedaralide (4), together with nine known analogues (5-13) were isolated from the branches and leaves of Aglaia lawii by RP C18 column, silica gel column, Sephadex LH-20 column chromatography and preparative HPLC. The structures of the new compounds were elucidated by IR, HRESIMS, 1D, 2D NMR, electronic circular dichroism (ECD) calculations and X-ray crystallography diffraction analysis. The results of bioassay showed that the compound 12 exhibited potential inhibitory activity against six human tumor cell lines (MDA-MB-231, MCF-7, Ln-cap, A549, HeLa and HepG-2) with IC50 values as 8.0-18.6 μM.

Unusual triterpenoids and steroids from Cipadessa baccifera and their biological activities

Five undescribed triterpenoids and steroids (1-5), as well as ten known compounds, were purified from the branches and leaves of Cipadessa baccifera. Notably, 1 and 2 are rare cipadesin-type limonoids with an unusual 8,30-epoxide ring and 1,8-ether linkage, respectively. Compound 5 possessed pregnane steroid skeleton with an uncommon 5/6/6/6/5-fused ring system. Their structures were constructed by extensive spectroscopic analysis (NMR, IR, UV, and HRESIMS), and their absolute configurations were confirmed by ECD calculations and quantum chemical calculations. All the isolates were in vitro assayed for their antimicrobial potentials against 6 pathogenic microorganisms and antiproliferation activities against five human cancer cell lines. As a result, compounds 5, 12, 13, and 14 exhibited moderate antibacterial activities (MIC: 25-50 μg/mL). Moreover, 5 showed cytotoxicity against five cancer cell lines with IC50 values ranging from 8.0 to 19.9 μM.

Synthesis of piscidinol A derivatives and their ability to inhibit HIV-1 protease

Four types of piscidinol A derivatives were synthesized and evaluated their ability to inhibit HIV-1 protease to understand their structure-activity relationships. Of these tirucallane-type triterpene derivatives, an A-seco derivative (1b) moderately inhibited human immunodeficiency virus (HIV) protease (IC50 38.2 μM). The 2,2-dimethyl succinic acid (DMS) acylated tirucallane derivatives (4b, 6a, and 7b, 50 < IC50 < 100 μM) were more inhibitory against HIV-1 PR than the others (PA, 2a, 4a, 4c-4d, 5a, 6b-6d, and 7a, IC50 > 100 μM). These findings indicated that the 2,3-seco-2,3-dioic acid (1b) and DMS-acylated tirucallane-type derivatives preferably inhibited HIV viral protease.

[The comparison of genetic divergences and its relationships to heterosis revealed by SSR and RFLP markers in rice (Oryza sativa L.)]

Genetic divergences of 57 entries from 6 ecotypes of rice were surveyed by PCR analysis with 48 pairs of SSR and by Southern analysis by 50 RFLP probes. It was indicated that SSR markers detected polymorphism efficiently in comparison to RFLP markers, considering the allele numbers per locus and average gene diversity. Among all of 1,596 pairs, 1,452 pairs of genetic distances based on SSR data (GDSSR) were higher than the genetic distance based on RFLP data (GDRFLP) by average of 0.2492. The average GDSSR of entries within indica subspecies was 0.5483, but GDRFLP was only 0.2776. And the GDSSR and GDRFLP of entries with japonica subspecies were 0.577, 0.2405 respectively. The average GDSSR between varieties of interspecies was 0.8074, and the average GDRFLP was 0.7310. It is suggested that the GDSSR between varieties of introspecies or interspecies are higher than that of GDRFLP. The analysis of correlation between GDSSR and GDRFLP of any entry with other 56 entries indicated that the correlation coefficient for typical Indica or Japonica varieties were higher, but lower for Indica-like or Japonica-like materials. It was also found that the relationships between genetic distance based on these two kinds of markers and the yield of hybrid performance were not significant, but most of the correlation coefficient between heterosis and GDRFLP or GDSSR arrived at highly significant level.