Anti-plasmodial and anti-inflammatory activities of cyclotide-rich extract and fraction of Oldenlandia affinis (R. & S.) D.C. (Rubiaceae).

BACKGROUND: Oldenlandia affinis, commonly called 'kalata-kalata', a versatile plant used locally to treat malaria fever in some parts of sub-Saharan Africa was investigated for anti-plasmodial and anti-inflammatory activities. OBJECTIVE: The study was designed to evaluate the antiplasmodial as well as anti-inflammatory activities of whole extract and cyclotide-rich fraction of Oldenlandia affinis. METHOD: The dichloromethane-methanol extract (ODE) of the plant, O. affinis was investigated for suppressive and curative antiplasmodial activities against Plasmodium berghei in mice. ODE and the cyclotide-rich fraction (CRF) was investigated for chronic and acute anti-inflammatory activities in rat models of inflammation. Inhibition of pro-inflammatory mediators was studied in RAW264.7 macrophages. RESULTS: ODE exhibited significant (p<0.05) reduction in mean parasitaemia in both the suppressive and curative models of Plasmodium berghei infection in mice.Administration of ODE(100, 200, or 400 mg/kg) and CRF (100, 200, or 400 mg/kg) produced significant inhibition of rodent models of acute and chronic inflammation . This observation is supported by the significant (P<0.05) inhibition of pro-inflammatory mediators, inducible nitric oxide (iNO) and tumour necrosis factor-alpha (TNF-α), and the reactive radical scavenging activities in RAW264.7 macrophages. CONCLUSION: These findings could explain, at least in part, the successes reported in the use of the herb, Oldenlandia affinis in the traditional treatment of malaria fever.

Herb-drug interaction between the extract of Hibiscus sabdariffa L. and hydrochlorothiazide in experimental animals.

Decoctions of Hibiscus sabdariffa L. (Family Malvaceae) are very popular for the preparation of homemade refreshing drinks and are also used medicinally for a variety of ailments. Particularly remarkable are the various scientific reports supporting diuretic and antihypertensive potentials. It is therefore not unusual for patients who are on orthodox antihypertensive medications to use medicinal H. sabdariffa drinks concomitantly without regard to the possibility of herb-drug interactions. This possibility necessitated this study in which the pharmacokinetic and pharmacodynamic interactions of H. sabdariffa extract (HSE) and hydrochlorothiazide (HCT), a commonly prescribed diuretic drug, were examined. The effects of concomitant administration of HSE on urine volume, urine pH, and urinary concentrations of sodium, bicarbonate, and chloride ions, as well as on the pharmacokinetic parameters of HCT, were determined in experimental rats and rabbits. Co-administration of HSE with HCT caused a significant increase in the volume of urine excreted and resulted in a decrease in the pH of urine and the concentrations of sodium, bicarbonate, and chloride ions. Co-administration of HSE (20-40 mg/kg) with HCT (10 mg/kg) increased and prolonged the plasma concentration, the mean area under the concentration-time curve, and the volume of distribution of HCT achieved over the 24-hour sampling period. The plasma clearance and the elimination rate constant of HCT decreased with increasing dose of HSE co-administered with the HCT. The results of this study reveal a possible herb-drug interaction involving HCT and HSE, used as an ingredient in medicinal or refreshing drinks in many countries.