Artabotrys crassifolius Hook. f. & Thomson is a medicinal plant used in Malaysia. The cytotoxic effects of the hexane, chloroform and ethanol extracts of the leaves and bark were examined in vitro against MCF-7, MDA-468 and HCT-116 cells. The chloroform extract of the bark inhibited the growth of all cell lines with GI 50 values ranging from 4.2 µg/mL to 9.4 µg/mL. Silica gel column chromatography of this extract yielded artabotrine, liridine, atherospermidine and lysicamine. Artabotrine and lysicamine inhibited the growth of HCT-116 and MCF-7 cells with GI 50 values ranging from 3.3 M to 3.9 M. These alkaloids were not toxic to human embryonic kidney cells (HEK297) up to a concentration of 50 g/mL.

Treatment of drug resistant protozoa, bacteria, and viruses requires new drugs with alternative chemotypes. Such compounds could be found from Southeast Asian medicinal plants. The present study examines the cytotoxic, antileishmanial, and antiplasmodial effects of 11 ethnopharmacologically important plant species in Malaysia. Chloroform extracts were tested for their toxicity against MRC-5 cells and Leishmania donovani by MTT, and chloroquine-resistant Plasmodium falciparum K1 strain by Histidine-Rich Protein II ELISA assays. None of the extract tested was cytotoxic to MRC-5 cells. Extracts of Uvaria grandiflora, Chilocarpus costatus, Tabernaemontana peduncularis, and Leuconotis eugenifolius had good activities against L. donovani with IC 50 < 50 µg/mL. Extracts of U. grandiflora, C. costatus, T. peduncularis, L. eugenifolius, A. subulatum, and C. aeruginosa had good activities against P. falciparum K1 with IC 50 < 10 µg/mL. Pinoresinol isolated from C. costatus was inactive against L. donovani and P. falciparum. C. costatus extract and pinoresinol increased the sensitivity of Staphylococcus epidermidis to cefotaxime. Pinoresinol demonstrated moderate activity against influenza virus (IC 50 = 30.4 ± 11 µg/mL) and was active against Coxsackie virus B3 (IC 50 = 7.1 ± 3.0 µg/mL). β-Amyrin from L. eugenifolius inhibited L. donovani with IC 50 value of 15.4 ± 0.01 µM. Furanodienone from C. aeruginosa inhibited L. donovani and P. falciparum K1 with IC 50 value of 39.5 ± 0.2 and 17.0 ± 0.05 µM, respectively. Furanodienone also inhibited the replication of influenza and Coxsackie virus B3 with IC 50 value of 4.0 ± 0.5 and 7.2 ± 1.4 µg/mL (Ribavirin: IC 50 : 15.6 ± 2.0 µg/mL), respectively. Our study provides evidence that medicinal plants in Malaysia have potentials as a source of chemotypes for the development of antiinfective leads.

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Parasites remain one of the most important causes of morbidity and mortality in the tropical landscape. Of these, granulomatous amoebic encephalitis (GAE), leishmaniasis and malaria are 3 common parasitic diseases which can be fatal if left untreated. The available drugs seem to be ineffective as resistant strains have emerged in recent years. It is timely for medicinal plants have been given much attention as an alternative for the available chemotherapeutic drugs. This review was conducted to evaluate the anti-parasitic effects of medicinal plants from different parts of the world. It was found that large numbers of plants showed strong anti-parasitic potential; Clerodendrum rotundifolium Oliv. leaves water fraction, Clerodendrum rotundifolium Oliv. leaves methanol fraction and Microglossa pyrifolia showed strong anti-malarial activity with IC50 of 0.01, 0.02 and 0.05 µg/ml in vitro. Limouni olive is a strong amoebicidal agent with IC50 of 5.11 µg/ml. Ethanol extracts from H. stignocarpa leaves (4.69 µg/ml), J. cuspidifolia leaves (10.96 µg/ml) and Jacaranda caroba leaves (13.22 µg/ml) showed strong activity against Leishmania spp. with IC50 values lower than 25 µg/ml. In conclusion, these promising results suggest that future research on medicinal plants needs to be done to identify its active constituents, cytotoxicity, effectivity and feasibility to be utilized against infections caused by these parasites. Furthermore, phytochemical investigations should be undertaken to achieve the effectiveness of therapeutic agents particularly in limited resource settings.

Malaria contributes to a major reason for the cause of fatality and serious health problems among children mainly in various parts of tropical Africa and Asia. The extraction of DNA plays a vital role in the diagnosis of this life-threatening parasite Plasmodium. Difficulties with existing extraction methods of DNA are increasing with time including detection limits, time duration, sensitivity, availability of chemicals, and cost. Consequently, there is now renewed interest in finding of novel methods for DNA extraction of Plasmodium. However, the extraction of DNA by using microwave irradiation is found to be most convenient and suitable due to its low-cost and usage of common chemical reagents especially for the children in poor resource settings. In addition, the low cost, noninvasive malaria diagnostics tests are needed to carry out particularly for children to avoid accidental infections which may happen due to drawing blood.