Nyctanthes arbor-tristis positively affects immunopathology of malaria-infected mice prolonging its survival

Medicinal plants as a fight against murine blood-stage malaria

OBJECTIVE

Malaria is an infectious parasitic disease affecting most of countries worldwide. Due to antimalarial drug resistance, researchers are seeking to find another safe efficient source for treatment of malaria. Since many years ago, medicinal plants were widely used for the treatment of several diseases. In general, most application is done first on experimental animals then human. In this article, medicinal plants as antimalarial agents in experimental animals were reviewed from January 2000 until November 2020.

MATERIALS AND METHODS

In this systematic review published articles were reviewed using the electronic databases NCBI, ISI Web of knowledge, ScienceDirect and Saudi digital library to check articles and theses for M.Sc/Ph.D. The name of the medicinal plant with its taxon ID and family, the used Plasmodium species, plant part used and its extract type and the country of harvest were described.

RESULTS AND CONCLUSION

The reviewed plants belonged to 83 families. Medicinal plants of families Asteraceae, Meliaceae Fabaceae and Lamiaceae are the most abundant for use in laboratory animal antimalarial studies. According to region, published articles from 33 different countries were reviewed. Most of malaria published articles are from Africa especially Nigeria and Ethiopia. Leaves were the most common plant part used for the experimental malaria research. In many regions, research using medicinal plants to eliminate parasites and as a defensive tool is popular.

A clerodane diterpene from Polyalthia longifolia as a modifying agent of the resistance of methicillin resistant Staphylococcus aureus

BACKGROUND

Staphylococcus aureus infections are raising serious concern across the world. The effectiveness of conventional drugs is continuously decreasing due to global emergence of multidrug resistance (MDR) and therefore, new resistance-modifying agents (RMAs) are highly needed.

HYPOTHESIS

Clerodane diterpene 16α-hydroxycleroda-3,13(14)-Z-dien-15,16-olide (CD) from leaves of Polyalthia longifolia (Sonn.) Thwaites (Annonaceae) as RAM will be useful in improving the current treatment strategies for staphylococcal infections.

STUDY DESIGN

In the present study, we determine the resistance-modifying activity of CD using clinical isolates of MRSA. Further, the influence of CD on innate immune response was also evaluated in vitro and in vivo. The nature of potential interactions was determined by fractional inhibitory concentration indices (FICIs) calculated from microdilution assays and time-kill curves.

RESULTS

The result of in vitro combination study showed that CD significantly reduced MIC of fluoroquinolones up to 16-folds (FICI 0.315-0.500), while in S. aureus infected Swiss albino mice model, combination of CD with norfloxacin, significantly (p<0.01, p<0.001) lowered the systemic microbial burden in blood, liver, kidney, lung and spleen tissues in comparison to CD, norfloxacin alone as well as untreated control. Flow cytometry analysis clearly showed that CD significantly inhibited EtBr efflux and extended post-antibiotic effect. In qRT-PCR analysis, CD alone as well as in combination, significantly modulated the expression of various efflux pump genes including norA up to 2-fold in clinical isolate MRSA-ST2071. Further, the in vitro combination study of the CD (10, 5, 2.5µg/ml) along with the norfloxacin (10µg/ml) depicted a significant decline in the pro-inflammatory cytokines, IL6 and TNF-α. In septic shock mice model, CD did not exhibit any significant changes in the level of pro-inflammatory cytokines.

CONCLUSION

This is the first report on drug resistance-modifying potential of CD through inhibition of MDR efflux pump.