The Decoction of Leaves of Phyllanthus discoideus Possesses Anticonvulsant and Sedative Properties in Mice

Anti-seizure effects of medicinal plants in Malawi on pentylenetetrazole-induced seizures in zebrafish larvae

ETHNOPHARMACOLOGICAL RELEVANCE

Medicinal plants are used to manage and treat epilepsy in Malawi because of traditional beliefs and barriers to conventional anti-seizure drugs. Among the plants prescribed by traditional medical practitioners are Margaritaria discoidea, Dalbergia boehmii, Dalbergia nitidula, Catunaregam spinosa, and Lannea discolor. Despite the wide use of these plants, there is a lack of scientific evidence to support their anti-seizure efficacy.

AIM OF THE STUDY

This study used the pentylenetetrazole (PTZ)-induced larval zebrafish seizure model to screen for anti-seizure effects of a collection of medicinal plants traditionally used in Malawi.

MATERIALS AND METHODS

Zebrafish larvae were incubated in decoctions at maximum tolerated concentrations for 18 h and exposed to PTZ. As a primary screen, the effects of the decoctions on seizure-induced locomotor activity were determined. Decoctions that significantly reduced total distance traveled were further checked for effects on seizure latency and frequency, brain activity, immediate early gene expression, and c-fos protein expression.

RESULTS

M. discoidea male leaves, D. boehmii roots, and D. nitidula leaves showed significant anti-seizure effects in the primary screen and were selected for further study. Electrophysiological and immediate early gene analyses corroborated anti-seizure effect of D. boehmii and D. nitidula. The results of c-fos protein expression further suggested that the anti-seizure effects in the larval brain may be mediated by the suppression of neurons localized in midbrain regions.

CONCLUSIONS

These findings provide pioneering scientific evidence of the presence of anti-seizure activity in M. discoidea, D. boehmii, and D. nitidula, prescribed by traditional Malawian medical practitioners. Further studies are needed to identify and isolate compounds responsible for such biological activities and elucidate the possible mechanisms of action.

Newtonoate as an active principle of Newtonia griffoniana for anxiolytic activity in Swiss mice

BACKGROUND

Newtonia griffoniana (Mimosaceae) is a Central African rain forest tree, whose bark extracts are used in Cameroonian folk medicine for the treatment of anxiety and sleep disorders.

METHODS

We evaluated the anxiolytic effects of N. griffoniana stem bark methanol extract and its major isolated constituent 2,3,4-trihydroxybutylpentatriacontanoate (newtonoate) on the elevated plus maze.

RESULTS

Significant increases in the percentage of entries into open arms were induced by both N. griffoniana extract (100 and 150 mg/kg BW; p<0.01) and newtonoate (doses of 3 and 15 mg/kg BW; p<0.05). Conversely, decreases in the percentage of entries into closed arms were observed at the same doses. In addition, N. griffoniana methanol extract (100 mg/kg) and the isolated newtonoate (30 mg/kg) induced significant (p<0.01 and p<0.05, respectively) increases in the time spent in the open arms, while inducing a decrease in the time spent in the closed arms. Newtonoate treatment also decreased head dipping number at doses of 3 and 15 mg/kg, while N. griffoniana methanol extract induced the same effect at 200 mg/kg.

CONCLUSIONS

These results suggest that N. griffoniana bark extract has anxiolytic properties, which justify its use in folk medicine. Such effects are at least partly mediated by newtonoate.

The Genus Phyllanthus: An Ethnopharmacological, Phytochemical, and Pharmacological Review

The plants of the genus Phyllanthus (Euphorbiaceae) have been used as traditional medicinal materials for a long time in China, India, Brazil, and the Southeast Asian countries. They can be used for the treatment of digestive disease, jaundice, and renal calculus. This review discusses the ethnopharmacological, phytochemical, and pharmacological studies of Phyllanthus over the past few decades. More than 510 compounds have been isolated, the majority of which are lignins, triterpenoids, flavonoids, and tannins. The researches of their remarkable antiviral, antioxidant, antidiabetic, and anticancer activities have become hot topics. More pharmacological screenings and phytochemical investigations are required to support the traditional uses and develop leading compounds.