Evaluation of anti-onchocercal activity of pseudopalmatine, a quaternary protoberberine alkaloid of Enantia chlorantha (Syn. <i>Annickia chlorantha</i>)

Abstract

Evaluation of anti-onchocercal activity of pseudopalmatine, a quaternary protoberberine alkaloid of Enantia chlorantha (Syn. Annickia chlorantha). ABSTRACT As part of our efforts towards identifying and subsequently developing lead compounds from medicinal plants of Cameroon to combat neglected tropical diseases, we embarked to phytochemically investigate Enantia chlorantha (Syn. Annickia chlorantha). The rationale for choosing this plant is its numerous uses in folk medicine in Cameroon and other parts of Africa. In Cameroon the quaternary protoberberine alkaloids, columbamine (2), palmatine (3) and jatrorrizine (4) have been isolated from the stem back and combined to produce a phytomedicine (HEPAZOR ® ) used in the treatment of viral hepatitis. An alkaloidal extraction of the methanolic extract of the stem bark of the plant was carried-out and this afforded yellow amorphous solids whose structure was obtained using routine nuclear magnetic resonance spectroscopy (NMR), high pressure liquid chromatography coupled to an electrospray mass spectrometer (HPLC-ESI-MS) and comparison with literature. The compound was identified as pseudopalmatine (1), a quaternary protoberberine alkaloid. Preliminary screening of the compound on both adult and juvenile worms of Onchocerca ochengi, a close relative of Onchocerca volvulus, the parasite responsible for human onchocerciasis (river blindness), showed that compound (1) was inactive at a concentration of 500 µg/ mL on the adult worms, but inhibited microfilariae motility completely at this same concentration and by 50 % at 250 µg/mL and was thus considered active. While this work to the best of our knowledge constitutes the first report on the anti-onchocercal activity of quaternary protoberberine alkaloids in general and pseudopalmatine (1) in particular isolated from E. Chlorantha, it has however opened a window for further investigation of the anti-onchoceral activity of this class of compounds. RÉSUMÉDans le cadre de nos efforts pour identifier et ensuite developer des substances naturelles ayant une activite antiparasitaires et antihelminthiques des plantes médicinales du Cameroun, nous nous sommes attelés à étudier Enantia chlorantha (Syn.Annickia chlorantha), une plante médicinale utiliser généralement au Cameroun pour le traitement des divers maladies parmi lesquels le palludisme, la rougeole et l'hépatite. Au Cameroun, les alcaloïdes tels que la columbamine (2), palmatine (3) et jatrorrhizine (4) isolé des ecorces de cette plante, sont combiner pour produire une phytomédicament (HEPAZOR ® ) appliquée dans le traitement du l'hépatite virale. L'extrait au méthanol des ecorces de cette plante à été sujet a une extraction des alcaloïdes. Une composé s'est cristallisée sous forme de poudre jaune et à été séparer et purifier. La structure de ce composé a été identifiée à celle du pseudopalmatine (1), un alcaloïde protoberberine quaternaire, sur la base des techniques spectroscopiques. La pseudopalmatine (1) a été soumis au teste sur les verres des macros et microfilair...

Phytochemical Screening, Total Polyphenols and Flavonoids Content and Antiradical Activity of Methanolic Extract of Annickia Chlorantha From Gabon

“…Some of these groups of compounds identified as alkaloids have several pharmacological activities, namely antimalarial (Uzor, 2020; Bribi, 2018), antibacterial (Kakpo et al, 2019), hepatoprotective (Jan et al, 2017). Some countries such as Cameroon have isolated aporphinic alkaloids (Wafo et al, 1999) and protoberberine alkaloids (Nyongbela et al, 2019) from Annickia chlorantha. Protoberberine alkaloids (palmatin, jatrorrhizine, columbamine) 929 isolated from the stem bark have been combined to make a phytodrug (HEPAZOR ® ) for the treatment of viral hepatitis (Nyongbela et al, 2019).…”

“…Some countries such as Cameroon have isolated aporphinic alkaloids (Wafo et al, 1999) and protoberberine alkaloids (Nyongbela et al, 2019) from Annickia chlorantha. Protoberberine alkaloids (palmatin, jatrorrhizine, columbamine) 929 isolated from the stem bark have been combined to make a phytodrug (HEPAZOR ® ) for the treatment of viral hepatitis (Nyongbela et al, 2019).…”