Krametosan, a new trinorlignan from the roots of Krameria tomentosa

Nor-Lignans: Occurrence in Plants and Biological Activities-A Review

In this review article, the occurrence of nor-lignans and their biological activities are explored and described. Nor-lignans have proven to be present in several different families also belonging to chemosystematically distant orders as well as to have many different beneficial pharmacological activities. This review article represents the first one on this argument and is thought to give a first overview on these compounds with the hope that their study may continue and increase, after this.

Raging the War Against Inflammation With Natural Products

Over the last few decade Non-Steroidal Anti-Inflammatory Drugs (NSAIDs) are the drugs of choice for treating numerous inflammatory diseases including rheumatoid arthritis. The NSAIDs produces anti-inflammatory activity via inhibiting cyclooxygenase enzyme, responsible for the conversation of arachidonic acid to prostaglandins. Likewise, cyclooxegenase-2 inhibitors (COX-2) selectively inhibit the COX-2 enzyme and produces significant anti-inflammatory, analgesic, and anti-pyretic activity without producing COX-1 associated gastrointestinal and renal side effects. In last two decades numerous selective COX-2 inhibitors (COXIBs) have been developed and approved for various inflammatory conditions. However, data from clinical trials have suggested that the prolong use of COX-2 inhibitors are also associated with life threatening cardiovascular side effects including ischemic heart failure and myocardial infection. In these scenario secondary metabolites from natural product offers a great hope for the development of novel anti-inflammatory compounds. Although majority of the natural product based compounds exhibit more selectively toward COX-1. However, the data suggest that slight structural modification can be helpful in developing COX-2 selective secondary metabolites with comparative efficacy and limited side effects. This review is an effort to highlight the secondary metabolites from terrestrial and marine source with significant COX-2 and COX-2 mediated PGE2 inhibitory activity, since it is anticipated that isolates with ability to inhibit COX-2 mediated PGE2 production would be useful in suppressing the inflammation and its classical sign and symptoms. Moreover, this review has highlighted the potential lead compounds including berberine, kaurenoic acid, α-cyperone, curcumin, and zedoarondiol for further development with the help of structure-activity relationship (SAR) studies and their current status.

A New Neolignan, and the Cytotoxic and Anti-HIV-1 Activities of Constituents from the Roots of Dasymaschalon sootepense

Bioassay-guided isolation from the ethyl acetate extract of Dasymaschalon sootepense roots led to the isolation of twelve compounds including a new dihydrobenzo-furan neolignan, (+)-(2S’,3S)-2,3-dihydro-2-(3,4-dimethoxyphenyl)-3-methylbenzofuran-5-carbaldehyde (5), and eleven known compounds (1-4, and 6-12). The chemical structures and stereochemistry of all the isolated compounds were established by spectroscopic techniques. The known compounds 4 and 6 have been fully characterized spectroscopically, including their absolute configurations. Cytotoxic and anti-HIV-1 reverse transcriptase (RT) activities of compounds 1-3, 5 and 8-12 were determined. Among compounds screened, compounds 2, 3 and 10 displayed weak cytotoxic activity with ED50 values ranging from 9.6-47.5 μM and only compound 2 was found weakly active against HIV-1 RT with an IC50 value of 323.2 μM.

Phytochemical study and anti-inflammatory, antidiabetic and free radical scavenger evaluations of Krameria pauciflora methanol extract

The plant Krameria pauciflora MOC et. Sessé ex DC. is used as an anti-inflammatory and antidiabetic in traditional medicine. The aim of this study was to evaluate the in vivo anti-inflammatory and antidiabetic effects of a methanol extract from the roots of K. pauciflora. Dichloromethane and ethyl acetate extracts obtained by partitioning the methanol extract were also evaluated. Complete methanol and dichloromethane extracts showed anti-inflammatory effects at 3 mg/kg. An anti-inflammatory effect similar to indomethacin (10 mg/kg) was observed when the methanol and dichloromethane extracts, which contain a cycloartane-type triterpene and an sterol, were administered orally at several doses (3, 10, 30 and 100 mg/kg), whereas no anti-inflammatory effect was observed at any dose for the ethyl acetate extract, which contains catechin-type flavonoids. The antidiabetic effect of each extract was also determined. An antihyperglycaemic effect was observed in diabetic rats, but no effect in normoglycaemic animals was observed when the methanol extract was administrated at 30 mg/kg. All of the extracts exhibited radical scavenger activity. Additionally, constituents from all of the extracts were identified by NMR. This article supports the use of K. pauciflora as an anti-inflammatory because it exhibits a similar effect to indomethacin. However, its antidiabetic effect is not completely clear, although it could be useful for preventing diabetic complications.

Synthesis of (-)-conocarpan by two routes based on radical cyclization and establishment of its absolute configuration

Two independent routes for the total synthesis of the bioactive neolignan (-)-conocarpan are described. The first (98% ee) is based on formal radical cyclization onto a benzene ring, and involves a 5-exo-trigonal closure onto a double bond restrained within a 6-membered ring. The second route (88% ee), which is shorter, is based on 5-exo-trigonal cyclization of an aryl radical onto a pendant terminal double bond. The two routes differ in their degree of stereoselectivity. The absolute configuration originally assigned to (+)-conocarpan had previously been called into question on the basis of empirical chiroptical rules; the present chemical work confirms the need for revision, and the assigned absolute configurations of several compounds correlated with (+)-conocarpan must also be changed.

Total synthesis of (−)-conocarpan and assignment of the absolute configuration by chemical methods

(-)-Conocarpan (1) was synthesized by a method based on radical cyclization, and the absolute configuration was established by chemical degradation; the original 2R,3R-assignment to (+)-conocarpan should be reversed, as suggested by a later chiroptical study of model 2,3-dihydrobenzofurans.