Antimalarial and safety evaluation of Pluchea lanceolata (DC.) Oliv. & Hiern: in-vitro and in-vivo study

Synthesis, molecular modelling studies of artemisinin-chalcone derivatives and their antimalarial activity evaluation

Twenty-two monomers and dimers of artemisinin having chalcone as a linker were synthesised, and their antimalarial activity against Plasmodium falciparum was determined, and a quantitative structure-activity relationship (QSAR) was developed. Artemisinin is a frontline antimalarial drug known worldwide but is threatened because of the rapidly emerging artemisinin-resistant strain Plasmodium falciparum. In vitro, antimalarial IC50 (half-maximal inhibitory concentration) activity of a molecule against malaria parasites provides a good first screen for identifying the antimalarial potential of a particular molecule. The most active compound was artemisinin dimer dimethoxy chalcone as a linker (22) with IC50 of 4.34 nM. The molecular mechanism was explored through in silico docking & ADMET studies for the active compounds.

Antibiotic Potentiation Through Phytochemical-Based Efflux Pump Inhibitors to Combat Multidrug Resistance Bacteria

BACKGROUND

Antimicrobial resistance development poses a significant danger to the efficacy of antibiotics, which were once believed to be the most efficient method for treating infections caused by bacteria. Antimicrobial resistance typically involves various mechanisms, such as drug inactivation or modification, drug target modification, drug uptake restriction, and drug efflux, resulting in decreased antibiotic concentrations within the cell. Antimicrobial resistance has been associated with efflux Pumps, known for their capacity to expel different antibiotics from the cell non-specifically. This makes EPs fascinating targets for creating drugs to combat antimicrobial resistance (AMR). The varied structures of secondary metabolites (phytomolecules) found in plants have positioned them as a promising reservoir of efflux pump inhibitors. These inhibitors act as modifiers of bacterial resistance and facilitate the reintroduction of antibiotics that have lost clinical effectiveness. Additionally, they may play a role in preventing the emergence of multidrug resistant strains.

OBJECTIVE

The objective of this review article is to discuss the latest studies on plant-based efflux pump inhibitors such as terpenoids, alkaloids, flavonoids, glycosides, and tetralones. It highlighted their potential in enhancing the effectiveness of antibiotics and combating the development of multidrug resistance.

RESULTS

Efflux pump inhibitors (EPIs) derived from botanical sources, including compounds like lysergol, chanaoclavine, niazrin, 4-hydroxy-α-tetralone, ursolic acid, phytol, etc., as well as their partially synthesized forms, have shown significant potential as practical therapeutic approaches in addressing antimicrobial resistance caused by efflux pumps. Further, several phyto-molecules and their analogs demonstrated superior potential for reversing drug resistance, surpassing established agents like reserpine, niaziridin, etc. Conclusion: This review found that while the phyto-molecules and their derivatives did not possess notable antimicrobial activity, their combination with established antibiotics significantly reduced their minimum inhibitory concentration (MIC). Specific molecules, such as chanaoclavine and niaziridin, exhibited noteworthy potential in reversing the effectiveness of drugs, resulting in a reduction of the MIC of tetracycline by up to 16 times against the tested strain of bacteria. These molecules inhibited the efflux pumps responsible for drug resistance and displayed a stronger affinity for membrane proteins. By employing powerful EPIs, these molecules can selectively target and obstruct drug efflux pumps. This targeted approach can significantly augment the strength and efficacy of older antibiotics against various drug resistant bacteria, given that active drug efflux poses a susceptibility for nearly all antibiotics.

Ameliorative Effects of Dietary Ellagic Acid Against Severe Malaria Pathogenesis by Reducing Cytokine Storms and Oxidative Stress

Ellagic acid (EA), a fruit- and vegetable-derived flavonoid, has been reported for multiple pharmacological activities, which encouraged us to examine its useful effect in severe malaria pathogenesis, especially malaria-induced cytokine storms and oxidative stress linked to damage in major organs. Malaria was induced by injecting Plasmodium berghei–infected RBCs intraperitoneally into the mice. EA was given orally (5, 10, and 20 mg/kg) following Peter’s 4-day suppression test. EA exhibited the suppression of parasitemia, production of inflammatory cytokine storms and oxidative stress marker level quantified from vital organs significantly and an increase in hemoglobin, blood glucose, and mean survival time compared to the vehicle-treated infected group. EA administration also restored the blood–brain barrier integrity evidenced through Evans blue staining. Furthermore, we demonstrated the protecting effect of EA in LPS-induced inflammatory cytokine storms and oxidative stress in glial cells. The present study conclude that ellagic acid is able to alleviate severe malaria pathogenesis by reducing cytokine storms and oxidative stress–induced by malarial parasites. It also attributed promising antimalarial activity and afforded to improve the blood glucose and hemoglobin levels in treated mice. These research findings suggested the suitability of ellagic acid as a useful bioflavonoid for further study for the management of severe malaria pathogenesis.

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.

Aromatic ginger (Kaempferia galanga L.) extracts with ameliorative and protective potential as a functional food, beyond its flavor and nutritional benefits

Aromatic ginger (Kaempferia galanga L) is native to India and believed to be originated in Burma. Despite substantial uses in a pickle and south-east Asian cuisines, aromatic ginger is chemically less studied than white and red ginger. Multi-directional investigations have been performed to evaluate chemical composition, nutritional values, ameliorative and protective potential of aromatic ginger (Kaempferia galanga) rhizome (KGR). Macro and micro components analysis confirmed that KGR contains protein, fiber, and high amount of essential minerals (potassium, phosphorous, and magnesium) along with appreciable amounts of iron, manganese, zinc, cobalt, and nickel. The anti-proliferative potential of KGR evaluated nine human cell lines. We have evaluated the anti-proliferative potential of hydrodistillate, extract, and key compound isolated from KGR on nine human cancer cell line and also reporting the safety to normal peritoneal macrophage cells. The current study demonstrates the anticancer potential of the KGR on MDA-MB-231 and WRL-68 cells. Very likely, results can be extrapolated to an animal or human system. Ethyl p-methoxy cinnamate (EPMC) was responsible for inhibiting the proliferation action which varied in a tested cell by intracellular reactive oxygen species (ROS) production. The present study demonstrates KGR as safe and high energy value medicinal spices with chemo-preventive action, without toxic phytochemicals, and tolerable other anti-nutritional factors.

Fraxetin and ethyl acetate extract from Lawsonia inermis L. ameliorate oxidative stress in P. berghei infected mice by augmenting antioxidant defence system

BACKGROUND

Lawsonia inermis L. is a well-documented plant for cosmetic as well as medicinal properties. It is used by local communities in India and Nigeria for the treatment of many parasitic diseases, including malaria.

HYPOTHESIS/PURPOSE

Earlier studies on the plant's antiplasmodial activity were not assigned to any phytochemical with no quality assurance data. In this report, a recent chemically characterized extract and it's major constituent were investigated for in vitro antiplasmodial activity on chloroquine sensitive NF-54 strain. Furtherly, the potent extract and this constituent were assessed in vivo in Plasmodium berghei infected mice. The bioactive phytochemical and enriched extract were also monitored against various oxidative stress parameters.

STUDY DESIGN/METHOD

The extract characterization was done by the quantitative analysis of eight phytochemicals using gradient reverse phase HPLC method. In vitro antiplasmodial activity was evaluated on chloroquine sensitive NF-54 strain by the determination of pfLDH activity. In vivo activity of the most potent extract and constituent were evaluated in P. berghei infected mice upon oral administration. The estimation of oxidative stress was done by monitoring various enzymatic and non-enzymatic parameters.

RESULTS

The ethyl acetate extract of leaves (IC₅₀ 9.00 ± 0.68 µg/ml) and fraxetin (IC₅₀ 19.21 ± 1.04 µM) were the most effective in in vitro assays therefore selected for in vivo tests. The administration of the ethyl acetate extract of leaves and fraxetin to the infected mice resulted in significant (p < .05) suppression of parasitaemia as evidenced by a 70.44 ± 2.58% to 78.77 ± 3.43% reduction compared to non-infected group. In addition, a two-fold increase in mean survival time, a significant (p < .05) reduction in lipid peroxidation and an elevation in glutathione, catalase and superoxide dismutase were also observed in treated mice. The post-infection treatment also led to an augmentation of endogenous antioxidant enzymes (GST, GR, GPx) with respect to the infected control. A significant (p < .05) elevation in serum Nrf2-antioxidant response element level responsible for the activation of endogenous enzymes was also observed.

CONCLUSION

It was evident from the experiments that ethyl acetate extract of L. inermis and fraxetin were able to suppress the oxidative damage by augmenting endogenous antioxidant system and thus ameliorated the plasmodium infection in mice.

A systematic review of pentacyclic triterpenes and their derivatives as chemotherapeutic agents against tropical parasitic diseases

Parasitic infections are among the leading global public health problems with very high economic and mortality burdens. Unfortunately, the available treatment drugs are beset with side effects and continuous parasite drug resistance is being reported. However, new findings reveal more promising compounds especially of plant origin. Among the promising leads are the pentacyclic triterpenes (PTs) made up of the oleanane, ursane, taraxastane, lupane and hopane types. This paper reviews the literature published from 1985 to date on the in vitro and in vivo anti-parasitic potency of this class of phytochemicals. Of the 191 natural and synthetic PT reported, 85 have shown high anti-parasitic activity against various species belonging to the genera of Plasmodium, Leishmania, Trypanosoma, as well as various genera of Nematoda. Moreover, structural modification especially at carbon 3 (C3) and C27 of the parent backbone of PT has led to improved anti-parasitic activity in some cases and loss of activity in others. The potential of this group of compounds as future alternatives in the treatment of parasitic diseases is discussed. It is hoped that the information presented herein will contribute to the full exploration of this promising group of compounds as possible drugs for parasitic diseases.

Diarylheptanoids Rich Fraction of Alnus nepalensis Attenuates Malaria Pathogenesis: In-vitro and In-vivo Study

Diarylheptanoids from Alnus nepalensis leaves have been reported for promising activity against filariasis, a mosquito-borne disease, and this has prompted us to investigate its anti-malarial and safety profile using in-vitro and in-vivo bioassays. A. nepalensis leaf extracts were tested in-vitro against chloroquine-sensitive Plasmodium falciparum NF54 by measuring the parasite specific lactate dehydrogenase activity. Among all, the chloroform extract (ANC) has shown promising anti-plasmodial activity (IC50 8.06 ± 0.26 µg/mL). HPLC analysis of ANC showed the presence of diarylheptanoids. Efficacy and safety of ANC were further validated in in-vivo system using Plasmodium berghei-induced malaria model and acute oral toxicity in mice. Malaria was induced by intra-peritoneal injection of P. berghei infected red blood cells to the female Balb/c mice. ANC was administered orally at doses of 100 and 300 mg/kg/day following Peter's 4 day suppression test. Oral administration of ANC showed significant reduction of parasitaemia and increase in mean survival time. It also attributed to inhibition of the parasite induced pro-inflammatory cytokines as well as afford to significant increase in the blood glucose and haemoglobin level when compared with vehicle-treated infected mice. In-vivo safety evaluation study revealed that ANC is non-toxic at higher concentration. Copyright © 2016 John Wiley & Sons, Ltd.

Pharmacological and phytochemical evaluation of Ocimum sanctum root extracts for its antiinflammatory, analgesic and antipyretic activities

Background:

Long-term use of nonsteroidal anti-inflammatory drugs (NSAIDs) increases risk of having a range of gastrointestinal problems. Therefore, new anti-inflammatory, analgesic, antipyretic drugs having lesser side effects are being searched all overthe world as alternatives to NSAIDs.

Aims:

To evaluate the anti-inflammatory, analgesic and antipyretic profile of Ocimum sanctum root extracts.

Materials and Methods:

Anti-inflammatory profile of hexane (STH), chloroform (STC), ethyl acetate (STE), butanol (STB) and water (STW) extracts of OS was carried out by using carrageenan induced paw edema. STE a most active extract was further validated in dose dependent manner for anti-inflammatory, analgesic and antipyretic activity as well as oral toxicity profile in small laboratory animals. Identification of bioactives flux and chemical signature of most active fraction STE was developed by using the high-performance liquid chromatography fingerprinting.

Results:

An ethyl acetate fraction (STE) exhibit most potent anti-inflammatory activity followed by STB, STW, STC and STH. Dose response study of STE showed anti-inflammatory, analgesic and anti-pyretic potential in dose-dependent manner without any toxic effect at dose 2000 mg/kg. Chemical fingerprint revealed the presence of flavanoids.

Conclusions:

The present research revealed that STE possess anti-inflammatory, analgesic and anti-pyretic properties. However, future research is advocated to evaluate the pharmacological properties of isolated bioactive compounds.

Box-Behnken design for optimum extraction of biogenetic chemicals from P. lanceolata with an energy audit (thermal × microwave × acoustic): a case study of HPTLC determination with additional specificity using on-line/off-line coupling with DAD/NIR/ESI-MS

INTRODUCTION

The genus Pluchea comprises about 80 species distributed worldwide, out of them, only Pluchea lanceolata (DC.) Oliv. & Hiern, is used extensively in the traditional system of India. No chromatographic method is available for its quality.

OBJECTIVES

To perform the energy audit for the extraction of biogenetic pentacyclic triterpene, its acetate and sterol from P. lanceolata utilising organic and four alternative solvents. Additionally to resolve the uncertainty of TLC determination, on-line/off-line coupling with a diode-array detector (DAD), and near-infrared (NIR) and electrospray ionisation (ESI) MS was introduced.

METHODS

The extraction of taraxasterol (Tx), taraxasterol acetate (TxAc) and stigmasterol (St) from P. lanceolata was performed using three energy modes. The effects of different operating parameters were studied for optimum extraction yield using the design of experiments, that is, the central composite design and Box-Behnken design. In addition to the retention factor (Rf ) and visible spectral matching, two additional optical spectroscopic techniques, that is, NIR and ESI-MS, were applied for extended specificity.

RESULTS

The method was developed for Tx, TxAc and St determination using HPTLC at 645 nm. The optimum extraction yield of targeted compounds was found to be higher with organic solvents than eco-friendly surfactants. The pulse ultrasonic assisted extraction (PUAE) has resulted in optimum extraction of compounds comparable to hot extraction. Both NIR and ESI-MS provided extended specificity in determination.

CONCLUSION

The 5/1-PUAE was determined to be effective, reproducible, simple and energy efficient for the determination of Tx, TxAc and St in P. lanceolata. The offline coupling of NIR and ESI-MS with HPTLC led to considerable improvement in specificity.