ABSTRACT
BACKGROUND & OBJECTIVES: Malaria is a deadly parasitic disease, having a high rate of incidence and mortality across the world. The spread and development of resistance against chemical insecticides is one of the major problems associated with malaria treatment and control. Hence, plant based formulations may serve as an alternative source towards development of new drugs for treatment of malaria. The present study was aimed to evaluate the in vitro antiplasmodial activities of leaf, stem and flower of Calotropis gigantea against chloroquine-sensitive Plasmodium falciparum (3D7 strain) and its cytotoxicity against THP-1 cell lines. The plant extract which showed highest potency, in the in vitro antimalarial activity was further tested in vivo against P. berghei (ANKA strain) for validating its efficacy. METHODS: The crude extracts of methanol, ethyl acetate and chloroform from leaves, stem and flowers of C. gigantea were prepared using Soxhlet apparatus. These extracts were screened for in vitro antimalarial activity against P. falciparum 3D7 strain. The cytotoxicity studies of crude extracts were conducted against THP-1 cell line. Phytochemical analysis of these extracts was carried out by following the standard methods. The damage to erythrocytes due to the plant extracts was tested. The in vivo study was conducted in P. berghei (ANKA) infected BALB/c albino mice by following the 4-day suppressive test. RESULTS: The phytochemical screening of the crude extracts showed the presence of alkaloids, flavonoids, triterpenes, tannins, carbohydrates, phenols, coumarins, saponins, phlobatannins and steroids. Out of all the extracts, the methanolic extract of leaves showed highest antimalarial activity with IC50 value of 12.17 µg/ml. In cytotoxicity evaluation, none of the crude extracts, showed cytotoxicity on THP-1 cell line. Since, methanolic leaf extract of C. gigantea showed good antimalarial activity in vitro, it was tested in vivo. In the in vivo results, the methanolic leaf extract of C. gigantea exhibited an excellent activity against P. berghei malaria parasite, wherein the decrement of parasite counts was moderately low and dose-dependent (p < 0.05) in comparison to the P. berghei infected control group, which showed a daily increase of parasitaemia unlike the chloroquine-treated group. INTERPRETATION & CONCLUSION: The methanolic leaf extract of C. gigantea may act as potent alternative source for development of new medicines or drugs for the treatment of drug-resistant malaria. Thus, further research is needed to characterize the bioactive molecules of the extracts of C. gigantea that are responsible for inhibition of malaria parasite.
Subject(s)
Antimalarials/pharmacology , Calotropis/chemistry , Phytochemicals/pharmacology , Plant Extracts/pharmacology , Plasmodium berghei/drug effects , Plasmodium falciparum/drug effects , Animals , Antimalarials/administration & dosage , Antimalarials/isolation & purification , Antimalarials/toxicity , Cell Survival/drug effects , Disease Models, Animal , Female , Flowers/chemistry , Humans , Inhibitory Concentration 50 , Malaria/drug therapy , Mice, Inbred BALB C , Monocytes/drug effects , Parasitic Sensitivity Tests , Phytochemicals/administration & dosage , Phytochemicals/isolation & purification , Phytochemicals/toxicity , Plant Extracts/administration & dosage , Plant Extracts/isolation & purification , Plant Extracts/toxicity , Plant Leaves/chemistry , Plant Stems/chemistry , THP-1 Cells , Treatment OutcomeABSTRACT
BACKGROUND: The objective of the current study was to assess the in vitro antiplasmodial activities of leaf, bark, flower, and the root of Pongamia pinnata against chloroquine-sensitive Plasmodium falciparum (3D7 strain), cytotoxicity against Brine shrimp larvae and THP-1 cell line. For in vivo study, the plant extract which has shown potent in vitro antimalarial activity was tested against Plasmodium berghei (ANKA strain). METHODS: The plant Pongamia pinnata was collected from the herbal garden of Acharya Nagarjuna University of Guntur district, Andhra Pradesh, India. Sequentially crude extracts of methanol (polar), chloroform (non-polar), hexane (non-polar), ethyl acetate (non-polar) and aqueous (polar) of dried leaves, bark, flowers and roots of Pongamia pinnata were prepared using Soxhlet apparatus. The extracts were screened for in vitro antimalarial activity against P. falciparum 3D7 strain. The cytotoxicity studies of crude extracts were conducted against Brine shrimp larvae and THP-1 cell line. Phytochemical analysis of the plant extracts was carried out by following the standard methods. The chemical injury to erythrocytes due to the plant extracts was checked. The in vivo study was conducted on P. berghei (ANKA) infected BALB/c albino mice by following 4-Day Suppressive, Repository, and Curative tests. RESULTS: Out of all the tested extracts, the methanol extract of the bark of Pongamia pinnata had shown an IC50 value of 11.67 µg/mL with potent in vitro antimalarial activity and cytotoxicity evaluation revealed that this extract was not toxic against Brine shrimp and THP-1 cells. The injury to erythrocytes analysis had not shown any morphological alterations and damage to the erythrocytes after 48 h of incubation. Because methanolic bark extract of Pongamia pinnata has shown good antimalarial activity in vitro, it was also tested in vivo. So the extract had exhibited an excellent activity against P. berghei malaria parasite while decrement of parasite counts was moderately low and dose-dependent (P < 0.05) when compared to the control groups, which shown a daily increase of parasitemia, unlike the CQ-treated groups. The highest concentration of the extract (1000 mg/kg b.wt./day) had shown 83.90, 87.47 and 94.67% of chemo-suppression during Suppressive, Repository, and Curative tests respectively which is almost nearer to the standard drug Chloroquine (5 mg/kg b.wt./day). Thus, the study has revealed that the methanolic bark extract had shown promisingly high ((P < 0.05) and dose-dependent chemo-suppression. The phytochemical screening of the crude extracts had shown the presence of alkaloids, flavonoids, triterpenes, tannins, carbohydrates, phenols, coumarins, saponins, phlobatannins and steroids. CONCLUSIONS: The present study is useful to develop new antimalarial drugs in the scenario of the growing resistance to the existing antimalarials. Thus, additional research is needed to characterize the bioactive molecules of the extracts of Pongamia pinnata that are responsible for inhibition of malaria parasite.
Subject(s)
Antimalarials/pharmacology , Millettia/chemistry , Plant Extracts/pharmacology , Plasmodium berghei/drug effects , Plasmodium falciparum/drug effects , Animals , Antimalarials/chemistry , Antimalarials/toxicity , Artemia/drug effects , Cell Line , Cell Survival/drug effects , Cells, Cultured , Erythrocytes/drug effects , Humans , Malaria/parasitology , Mice , Mice, Inbred BALB C , Parasitemia/parasitology , Plant Bark/chemistry , Plant Extracts/chemistry , Plant Extracts/toxicityABSTRACT
The present work deals with the development of Plasmodium falciparum stages in mouse model and its potential for the study of efficacy of antimalarial drugs. C57BL/6J mice were infected with multidrug resistant P. falciparum strain then treated with arteether and artesunate. A response was observed to antimalarial drugs in terms of decrease in parasitemia. Mice infected with P. falciparum strain were successfully cured after treatment with either arteether or artesunate. The speed of parasite clearance time and burden of parasitemia differed for each drug and matched the previously reported observations, hence stressing the relevance of the model. These findings thus suggest that P. falciparum infected human RBC (iRBC) - C57BL/6J mice can provide a valuable in vivo system and should be included in the short list of animals that can be used for the evaluation of P. falciparum responses to drugs.
