Triterpene and coumarins from Skimmia laureola

Plant Coumarins with Anti-HIV Activity: Isolation and Mechanisms of Action

This review summarizes and systematizes the literature on the anti-HIV activity of plant coumarins with emphasis on isolation and the mechanism of their antiviral action. This review summarizes the information on the anti-HIV properties of simple coumarins as well as annulated furano- and pyranocoumarins and shows that coumarins of plant origin can act by several mechanisms: inhibition of HIV reverse transcriptase and integrase, inhibition of cellular factors that regulate HIV-1 replication, and transmission of viral particles from infected macrophages to healthy ones. It is important to note that some pyranocoumarins are able to act through several mechanisms or bind to several sites, which ensures the resistance of these compounds to HIV mutations. Here we review the last two decades of research on the anti-HIV activity of naturally occurring coumarins.

Coumarins from Magydaris pastinacea as inhibitors of the tumour-associated carbonic anhydrases IX and XII: isolation, biological studies and in silico evaluation

In an in vitro screening for human carbonic anhydrase (hCA) inhibiting agents from higher plants, the petroleum ether and ethyl acetate extracts of Magydaris pastinacea seeds selectively inhibited hCA IX and hCA XII isoforms. The phytochemical investigation of the extracts led to the isolation of ten linear furocoumarins (1-10), four simple coumarins (12-15) and a new angular dihydrofurocoumarin (11). The structures of the isolated compounds were elucidated based on 1 D and 2 D NMR, MS, and ECD data analysis. All isolated compounds were inactive towards the ubiquitous cytosolic isoform hCA I and II (K_i > 10,000 nM) while they were significantly active against the tumour-associated isoforms hCA IX and XII. Umbelliprenin was the most potent coumarin inhibiting hCA XII isoform with a K_i of 5.7 nM. The cytotoxicity of the most interesting compounds on HeLa cancer cells was also investigated.

Bioactive prenylated coumarins as potential anti-inflammatory and anti-HIV agents from Clausena lenis

The phytochemical study on the stems of Clausena lenis resulted in the isolation of three new prenylated coumarins, clauselenins A-C (1-3), together with nine known prenylated coumarins (4-12). The chemical structures of new prenylated coumarins (1-3) were elucidated by means of comprehensive spectral analyses and the known compounds (4-12) were determined by means of comparing their experimental spectral data with those described data in the literatures. All isolated prenylated coumarins were assessed for their anti-inflammatory effects together with anti-HIV activities in vitro. Prenylated coumarins 1-12 displayed remarkable inhibitory effects against nitric oxide (NO) production induced by lipopolysaccharide in mouse macrophage RAW 264.7 cells in vitro with the IC₅₀ values which are comparable to hydrocortisone. Meanwhile, prenylated coumarins 1-12 exhibited considerable anti-HIV-1 reverse transcriptase (RT) activities possessing EC₅₀ values in the range of 0.17-9.08 µM. These findings indicate that the isolation and identification of these prenylated coumarins with pronounced anti-inflammatory effects as well as anti-HIV activities separated from the stems of C. lenis could be of great significance to the development of new anti-inflammatory and anti-HIV agents and their potential applications in the pharmaceutical industry.

Prenylated Coumarins from the Fruits of Manilkara zapota with Potential Anti-inflammatory Effects and Anti-HIV Activities

Manilkara zapota, usually known as Sapodilla, is a fairly slow-growing evergreen tropical tree which belongs to the genus Manilkara (Sapotaceae), indigenous to Central America, southern Mexico, and the Caribbean. The ripe fruits of M. zapota have been widely consumed as an uniquely flavored tropical fruit and verified to hold a variety of health benefits. In order to investigate the potential health-promoting chemical compositions from the fruits of M. zapota cultivated in Hainan Island of China, a systematic and in-depth phytochemical study on this fruit was accordingly implemented. In our current study, three new prenylated coumarins, manizapotins A-C (1-3), together with seven known prenylated coumarins (4-10), were separated from the fruits of M. zapota. The chemical structures of new prenylated coumarins 1-3 were unambiguously established by means of comprehensive spectroscopic analyses, and the known compounds 4-10 were determined by comparing their experimental spectral data with those described data in the literature. This is the first time to discover prenylated coumarins occurring in M. zapota. The potential anti-inflammatory effects and anti-HIV (human immunodeficiency virus) activities of all these separated prenylated coumarins were assessed. Prenylated coumarins 1-10 dispalyed remarkable inhibitory effects against nitric oxide production induced by lipopolysaccharide in mouse macrophage RAW 264.7 cells with the IC₅₀ values equivalent to that of hydrocortisone in vitro. Meanwhile, prenylated coumarins 1-10 exhibited pronounced anti-HIV-1 reverse transcriptase activities with the EC₅₀ values in range of 0.12-8.69 μM. These results suggest that appropriate and reasonable consumption of the fruits of M. zapota might assist people to prevent and reduce the occurrence of inflammatory diseases together with the infection of HIV. Furthermore, the discovery of these prenylated coumarins from the fruits of M. zapota holding pronounced anti-inflammatory effects along with anti-HIV activities could be of great significance to the research and development of new natural anti-inflammatory and anti-HIV agents.

New Anti-inflammatory Triterpene Esters and Glycosides from Alstonia scholaris

BACKGROUND

Phytochemical studies on the ethanolic extract of aerial parts of Alstonia scholaris lead to the isolation of two new triterpenoid of the lanostanetype, lanosta 5ene,24-ethyl-3-O-β-D-glucopyranoside (1), lanosta,5ene,24-ethyl-3-O-β-D-glucopyranosideester (2) and new ursane type triterpenoidmethylester, 12-ursene-2,3,18,19-tetrol,28 acetate (nighascholarene) (3), together with seven known triterpenes, betuline, triterpene of the lupane type, alstoprenyol (4), 3β-hydroxy-28-β-acetoxy-5-olea triterpene (5),α-amyrin acetate (6), α-amyrin (7), lupeol acetate (8), 3β-hydroxy-24-nor-urs-4,12,28-triene triterpene (9) and ursolic acid (l0).

METHODOLOGY

The triterpenoid structures of these colorless compounds were deduced from the 1H and 13C-NMR data, and in particular from the application of two-dimensional 1H, 13C correlation experiments as well as by comparison with reported literature data.

CONCLUSION

This study deals with isolation and structural elucidation of natural new triterpenoidesters and glycosides with anti-inflammatory activity.

Phytochemistry of the genus Skimmia (Rutaceae)

The genus Skimmia is a rich source of interesting secondary metabolites, including 20 alkaloids derived from anthranilic acid, 45 coumarins, 21 limonoids, four cholestane derivatives, six pentacyclic triterpenes, six flavonoids, and two unusual fatty acid derivatives. Skimmia is employed in folk medicine e.g. against fever, inflammations, and rheumatism. Skimmia extracts, Skimmia essential oils and pure compounds isolated from Skimmia extracts have been experimentally shown to have various bioactivities such as antioxidant, anti-inflammatory, antimicrobial, and insecticidal. In this review we discuss the exact structures of compounds isolated from members of the genus Skimmia, bioactivities of Skimmia extracts and pure compounds derived from them, and systematic implications of the patterns of occurrence of these compounds. Moreover, research gaps and interesting avenues for future research are discussed briefly.

In vivo screening of essential oils of Skimmia laureola leaves for antinociceptive and antipyretic activity

OBJECTIVE

To study the screening of essential oils of Skimmia laureola leaves (SLO) for acute toxicity, antinociceptive, antipyretic and anticonvulsant activities in various animal models.

METHODS

SLO were extracted using modified Clevenger type apparatus. Acute toxicity test was used in mice to observe its safety level. Antinociceptive activity of SLO was evaluated in acetic acid induced writhing and hot plate tests. Yeast induced hyperthermic mice and pentylenetetrazole induced convulsive mice were used for the assessment of its antipyretic and anticonvulsant profile respectively.

RESULTS

Substantial safety was observed for SLO in acute toxicity test. SLO showed a high significant activity in acetic acid induced writhing test in a dose dependent manner with maximum pain attenuation of 68.48% at 200 mg/kg i.p. However, it did not produce any relief in thermal induced pain at test doses. When challenged against pyrexia evoked by yeast, SLO manifested marked amelioration in hyperthermic mice, dose dependently. Maximum anti-hyperthermic activity (75%) was observed at 200 mg/kg i.p. after 4 h of drug administration. Nevertheless, SLO had no effect on seizures control and mortality caused by pentylenetetrazole.

CONCLUSIONS

In vivo studies of SLO showed prominent antinociceptive and antipyretic activities with ample safety profile and thus provided pharmacological base for the traditional uses of the plant in various painful conditions and pyrexia. Additional detail studies are required to ascertain its clinical application.

Triterpenoids

This review covers the isolation and structure determination of triterpenoids including squalene derivatives, lanostanes, cycloartanes, dammaranes, euphanes, tirucallanes, tetranortriterpenoids, quassinoids, lupanes, oleannes, friedelanes, ursanes, hopanes, isomalabaricanes and saponins. The literature from January to December 2002 is reviewed and 221 references are used.