Skeletal hybridization and PfRIO-2 kinase modeling for synthesis of α-pyrone analogs as anti-malarial agent

Curcumin and Its Derivatives as Potential Antimalarial and Anti-Inflammatory Agents: A Review on Structure-Activity Relationship and Mechanism of Action

Curcumin, one of the major ingredients of turmeric (Curcuma longa), has been widely reported for its diverse bioactivities, including against malaria and inflammatory-related diseases. However, curcumin's low bioavailability limits its potential as an antimalarial and anti-inflammatory agent. Therefore, research on the design and synthesis of novel curcumin derivatives is being actively pursued to improve the pharmacokinetic profile and efficacy of curcumin. This review discusses the antimalarial and anti-inflammatory activities and the structure-activity relationship (SAR), as well as the mechanisms of action of curcumin and its derivatives in malarial treatment. This review provides information on the identification of the methoxy phenyl group responsible for the antimalarial activity and the potential sites and functional groups of curcumin for structural modification to improve its antimalarial and anti-inflammatory actions, as well as potential molecular targets of curcumin derivatives in the context of malaria and inflammation.

Isolation and quantification of antimalarial N-alkylamides from flower-head derived in vitro callus cultures of Spilanthes paniculata

This is the pioneer work reporting on simple procedure for synchronized determination and quantification of two biologically active N-alkylamides, (2E,6Z,8E)-N-isobutyl-2,6,8-decatrienamide (spilanthol) and (2E,4Z)-N-isobutyl-2,4-undecadiene-8,10-diynamide (UDA), using in vitro callus cultures from flower-heads of Spilanthes paniculata. The extracts were purified using preparative thin layer chromatography (TLC) and finest separation of compounds was optimized using high performance liquid chromatography (HPLC). Eventually, N-alkylamides were validated by mass spectrometry. Linearity curve with its regression coefficients (R²) obtained for both these alkylamides was 0.99. While spilanthol was quantified using tentative standard dodeca-2(E),4(E)-dienoic acid due to the non-availability of commercial standard and the precision of a developed method was evaluated in terms of relative standard deviation by measuring inter- and intra-days variation 3.52% and 1.74%, respectively. Similarly, calibration curve was obtained for the compound UDA isolated from flower-head explants from field grown parental plant with its inter- and intra-day RSD values as 4.33% and 3.61%, respectively. With this protocol, a very high yield of 2.23 mg/g of spilanthol and 4.30 mg/g dry weight (DW) of UDA, was obtained, simultaneously, from callus cultures. Flower-heads from parent plants, used as control, showed negligible amount of spilanthol and quantity of UDA was marginally higher than that in callus cultures. The highly stable biotherapeutic spilanthol and UDA with m/z 222 and m/z 230, respectively, showed retardation of malaria parasite development through blockage at ring stage of erythrocytic schizogony and ultimately lead to parasite death. The effect on parasite was additive. This study signifies the utility of in vitro cell cultures for therapeutic compound production, throughout the year, at higher yield for down-stream applications.

New insight-guided approaches to detect, cure, prevent and eliminate malaria

New challenges posed by the development of resistance against artemisinin-based combination therapies (ACTs) as well as previous first-line therapies, and the continuing absence of vaccine, have given impetus to research in all areas of malaria control. This review portrays the ongoing progress in several directions of malaria research. The variants of RTS,S and apical membrane antigen 1 (AMA1) are being developed and test adapted as multicomponent and multistage malaria control vaccines, while many other vaccine candidates and methodologies to produce antigens are under experimentation. To track and prevent the spread of artemisinin resistance from Southeast Asia to other parts of the world, rolling circle-enhanced enzyme activity detection (REEAD), a time- and cost-effective malaria diagnosis in field conditions, and a DNA marker associated with artemisinin resistance have become available. Novel mosquito repellents and mosquito trapping and killing techniques much more effective than the prevalent ones are undergoing field testing. Mosquito lines stably infected with their symbiotic wild-type or genetically engineered bacteria that kill sympatric malaria parasites are being constructed and field tested for stopping malaria transmission. A complementary approach being pursued is the addition of ivermectin-like drug molecules to ACTs to cure malaria and kill mosquitoes. Experiments are in progress to eradicate malaria mosquito by making it genetically male sterile. High-throughput screening procedures are being developed and used to discover molecules that possess long in vivo half life and are active against liver and blood stages for the fast cure of malaria symptoms caused by simple or relapsing and drug-sensitive and drug-resistant types of varied malaria parasites, can stop gametocytogenesis and sporogony and could be given in one dose. Target-based antimalarial drug designing has begun. Some of the putative next-generation antimalarials that possess in their scaffold structure several of the desired properties of malaria cure and control are exemplified by OZ439, NITD609, ELQ300 and tafenoquine that are already undergoing clinical trials, and decoquinate, usnic acid, torin-2, ferroquine, WEHI-916, MMV396749 and benzothiophene-type N-myristoyltransferase (NMT) inhibitors, which are candidates for future clinical usage. Among these, NITD609, ELQ300, decoquinate, usnic acid, torin-2 and NMT inhibitors not only cure simple malaria and are prophylactic against simple malaria, but they also cure relapsing malaria.