Isolation of cleomin from roots of Ritchiea longipedicillata

Natural Product Isolation of the Extract of Cleome rupicola Fruits Exhibiting Antioxidant Activity

Cataracts are the leading cause of blindness worldwide, however, there is currently no drug-based treatment. Plants that exhibit antioxidant properties have shown promising anticataract effects, likely because they supplement the activity of glutathione, the major antioxidant in lens cells. An extract of Cleome rupicola, a desert plant found in the United Arab Emirates, has traditionally been used to treat cataracts. Phytochemical screening of the aqueous extract established the presence of flavonoids, tannins, steroid derivatives, and reducing sugars. Fractioning of extracts from the fruits using high-performance liquid chromatography (HPLC) yielded the isolation of the anthelmintic compound cleomin, and its structure was confirmed using mass spectrometry (MS) and nuclear magnetic resonance (NMR) spectroscopy.

Cleomin Exerts Acute Antinociceptive Effects in Mice via GABAB and Muscarinic Receptors

Cleomin, a 1,3-oxazolidine-2-thione, was recently isolated from Neocalyptrocalyx longifolium, a species traditionally used for treating painful conditions. Reports about the pharmacological activities of cleomin are lacking. Here, the antinociceptive effects of cleomin were investigated using mice models of pain, namely the formalin, the cold plate, and the tail flick tests. Motor integrity was assessed in the rota-rod test. Antagonism assays and in silico docking analyses were performed to investigate the putative mechanisms of action. Cleomin (12.5-25 mg/kg), at doses that did not induce motor impairment, induced dose-dependent antinociception in both early and late phases of the formalin test and reduced nociceptive behaviors in both the cold plate and tail flick tests. Pretreatments with phaclofen and atropine attenuated the antinociceptive effects of cleomin, implicating the involvement of GABAB and muscarinic receptors. In silico docking studies suggested satisfactory coupling between cleomin and GABAB and M2 receptors, hence corroborating their role in cleomin's activity. Pretreatments with naloxone, yohimbine, bicuculline, and methysergide did not affect the antinociception of cleomin. In silico pharmacokinetics prediction showed a good drug ability profile of cleomin. In conclusion, cleomin promoted antinociception mediated by GABAB and muscarinic receptors. These findings support further investigation of the analgesic potential of cleomin.

Antimicrobial and antiplasmodial activities of a quaternary compound from Ritchiea capparoides var. longipedicellata

The leaves of Ritchiea capparoides var. longipedicellata (Capparidaceae) is used in ethnomedicine in South-Western Nigeria to treat infectious and parasitic diseases. This study was aimed at identifying the compound(s) that are responsible for the antimicrobial and antiplasmodial activities of the leaves and also to contribute to the chemistry of the plant species. A 70 % aqueous ethanolic extract of the leaves of R. longipedicellata was subjected to repeated liquid chromatographic methods on silica gel, Lobar RP-18 column and Sephadex LH-20 to isolate a Draggendorf positive compound. The compound was identified by (1)H and (13)C NMR, ultra-violet spectroscopy and polarimetry. The antimicrobial activity of the compound was evaluated using the microbroth dilution method while the antiplasmodial activity was carried out according to Trager and Jenson (1976). The minimum inhibitory concentration (MIC) was expressed in mg/ml. The isolated compound, leavoisomer of stachydrine, inhibited the growth of Escherichia coli NCTC 8196 and Staphylococcus aureus NCTC 6571 at the MIC of 5 mg/ml. In the anti-malaria assay, the compound had inhibitory activity with the concentration required to cause 100% lethality being 0.667 mg/ml.

CONCLUSION

The antibacterial and antiparasitic effects of quaternary ammonium compounds are well documented. However, this study is the first report of the presence and biological activities of this compound in this plant species which may justify the ethnomedicinal uses of the leaves.