Catechin Isolated from Garcinia celebica Leaves Inhibit Plasmodium falciparum Growth through the Induction of Oxidative Stress

Phytochemical profile and diverse pharmacology of Garcinia celebica L

Garcinia celebica L. syn. Garcinia hombroniana Pierre belongs to the family Clusiaceae, is indigenous to Southeast Asian countries. This review aims to provide updated, comprehensive and categorized information on the phytoconstituents and pharmacological effects of this species. The data collection mainly involved searches through databases named Scopus, Google Scholar, Pubmed and Springer Link. Approximately 100 phytochemicals were recorded in this review, with various classes of compounds such as triterpenoids, flavonoids, benzophenones, xanthones, depsidones and sterols identified. The most abundant compounds isolated belong to two chemical classes: triterpenoids and xanthones. Their extracts and pure compounds have been reported for their antibacterial, antiparasitic, hepatoprotective, antioxidant, antidiabetic, antituberculosis, antiplatelet aggregation, anti-neuraminidase and cholinesterase inhibitory activities. This review will provide a comprehensive understanding between the phytochemical components and its medicinal uses that may serve as a valuable resource for future drug development.

Phenolic-rich extracts from toasted white and tannin sorghum flours have distinct profiles influencing their antioxidant, antiproliferative, anti-adhesive, anti-invasive, and antimalarial activities

Sorghum is a gluten-free cereal commonly used in foods, and its consumption has been associated with the prevention of human chronic conditions such as obesity and cancer, due to the presence of dietary fiber and phenolic compounds. This study aimed to evaluate, for the first time, the antiproliferative, antioxidant, anti-adhesion, anti-invasion, and antimalarial activities of phenolic extracts from toasted white and tannin sorghum flours to understand how different phenolic profiles contribute to sorghum biological activities. Water and 70 % ethanol/water (v/v), eco-friendly solvents, were used to obtain the phenolic extracts of toasted sorghum flours, and their phenolic profile was analyzed by UPLC-MSE. One hundred forty-five (145) phenolic compounds were identified, with 23 compounds common to all extracts. The solvent type affected the phenolic composition, with aqueous extract of both white sorghum (WSA) and tannin sorghum (TSA) containing mainly phenolic acids. White sorghum (WSE) and tannin sorghum (TSE) ethanolic extracts exhibited a higher abundance of flavonoids. WSE demonstrated the lowest IC50 on EA.hy926 (IC50 = 46.6 µg/mL) and A549 cancer cells (IC50 = 33.1 µg/mL), while TSE showed the lowest IC50 (IC50 = 70.8 µg/mL) on HCT-8 cells (human colon carcinoma). Aqueous extracts also demonstrated interesting results, similar to TSE, showing selectivity for cancer cells at higher IC50 concentrations. All sorghum extracts also reduced the adhesion and invasion of HCT-8 cells, suggesting antimetastatic potential. WSE, rich in phenolic acids and flavonoids, exhibited greater toxicity to both the W2 (chloroquine-resistant) and 3D7 (chloroquine-sensitive) strains of Plasmodium falciparum (IC50 = 8 µg GAE/mL and 22.9 µg GAE/mL, respectively). These findings underscore the potential health benefits of toasted sorghum flours, suggesting diverse applications in the food industry as a functional ingredient or even as an antioxidant supplement. Moreover, it is suggested that, besides the phenolic concentration, the phenolic profile is important to understand the health benefits of sorghum flours.

Antiplasmodial and Antileishmanial Activities of a New Limonoid and Other Constituents from the Stem Bark of Khaya senegalensis

Plasmodium falciparum and Leishmania sp. resistance to antiparasitic drugs has become a major concern in malaria and leishmaniasis control. These diseases are public health problems with significant socioeconomic impacts, and mostly affect disadvantaged populations living in remote tropical areas. This challenge emphasizes the need to search for new chemical scaffolds that preferably possess novel modes of action to contribute to antimalarial and antileishmanial research programs. This study aimed to investigate the antimalarial and antileishmanial properties of a methanol extract (KS-MeOH) of the stem bark of the Cameroonian medicinal plant Khaya senegalensis and its isolated compounds. The purification of KS-MeOH led to the isolation of a new ordered limonoid derivative, 21β-hydroxybourjotinolone A (1a), together with 15 known compounds (1bc-14) using a repeated column chromatography. Compound 1a was obtained in an epimeric mixture of 21α-melianodiol (1b) and 21β-melianodiol (1c). Structural characterization of the isolated compounds was achieved with HRMS, and 1D- and 2D-NMR analyses. The extracts and compounds were screened using pre-established in vitro methods against synchronized ring stage cultures of the multidrug-resistant Dd2 and chloroquine-sensitive/sulfadoxine-resistant 3D7 strains of Plasmodium falciparum and the promastigote form of Leishmania donovani (1S(MHOM/SD/62/1S). In addition, the samples were tested for cytotoxicity against RAW 264.7 macrophages. Positive controls consisted of artemisinin and chloroquine for P. falciparum, amphotericin B for L. donovani, and podophyllotoxin for cytotoxicity against RAW 264.7 cells. The extract and fractions exhibited moderate to potent antileishmanial activity with 50% inhibitory concentrations (IC50) ranging from 5.99 ± 0.77 to 2.68 ± 0.42 μg/mL, while compounds displayed IC50 values ranging from 81.73 ± 0.12 to 6.43 ± 0.06 μg/mL. They were weakly active against the chloroquine-sensitive/sulfadoxine-resistant Pf3D7 strain but highly potent toward the multidrug-resistant PfDd2 (extracts, IC50 2.50 ± 0.12 to 4.78 ± 0.36 μg/mL; compounds IC50 2.93 ± 0.02 to 50.97 ± 0.37 μg/mL) with selectivity indices greater than 10 (SIDd2 > 10) for the extract and fractions and most of the derived compounds. Of note, the limonoid mixture [21β-hydroxylbourjotinolone A (1a) + 21α-melianodiol (1b) + 21β-melianodiol (1c)] exhibited moderate activity against P. falciparum and L. donovani. This novel antiplasmodial and antileishmanial chemical scaffold qualifies as a promising starting point for further medicinal chemistry-driven development of a dually active agent against two major infectious diseases affecting humans in Africa.

In Vivo Antimalarial Activity of the Leaf Extract of Osyris quadripartita Salzm. ex Decne and Its Major Compound (-) Catechin

Background

The leaves of Osyris quadripartita Salzm. ex Decne, endemic to Ethiopia, are traditionally used for the treatment of malaria. Previous phytochemical investigations of Osyris species showed the presence of flavonoids, anthracene derivatives, and sesquiterpene lactones as the main constituents. The aim of the present study was to investigate the antimalarial activity of the leaf extract of O. quadripartita and its isolated constituent against mice infected with Plasmodium berghei.

Methods

Isolation of a compound was carried out on silica gel column chromatography of the extract eluting with gradient mixtures of CHCl3/MeOH. Structural elucidation of the isolated compound was achieved by ESI-MS and 1D-and 2D-NMR spectral data. Peter's 4-day suppressive test method was used to determine the antimalarial activity of the test substances. Level of parasitemia, survival time, and body weight change were used to determine the antimalarial activity of the test substances.

Results

(-) Catechin was isolated and characterized from the hydroalcoholic extract of O. quadripartita. At a concentration of 400 mg/kg, both the extract and (-) catechin exhibited antimalarial activity with the highest chemosuppression values of 70.61% and 64.26%, respectively.

Conclusion

These findings indicate that O. quadripartita is endowed with genuine antimalarial activity attributed in part, to its (-) catechin content. Hence, the present study may validate the traditional use of the plant for the treatment of malaria.

Antioxidant and Antimicrobial Activities of the Extracts from Different Garcinia Species

Background

Garcinia is a large genus which has promising bioactivities. However, the properties of many Garcinia species have not been investigated thoroughly.

Aim

To determine the antioxidant and antimicrobial capabilities of the extracts from different Garcinia species. Methodology. Six Garcinia species, including Garcinia fusca, Garcinia hopii, Garcinia planchonii, Garcinia nigrolineata, Garcinia gaudichaudii, and Garcinia tinctoria were extracted using n-hexane, ethyl acetate, and methanol, producing n-hexane extract (HE), ethyl acetate extract (EAE), and methanol extract (ME). After that, the total polyphenol content was evaluated using Folin–Ciocalteu assay. DPPH, hydroxyl radical scavenging, and total antioxidant capacity assays were performed to test the antioxidant activity. Subsequently, the antimicrobial activities against Gram-positive (Staphylococcus aureus, Bacillus subtilis) and Gram-negative (Escherichia coli, Pseudomonas aeruginosa) bacterial strains were assessed using Kirby Bauer and the broth microdilution methods.

Results

Many Garcinia extracts contained high total polyphenol content consisting of ME of G. hopii ad G. tinctoria, and EAE of G. planchonii and G. tinctoria. The EAE of G. tinctoria showed effective antioxidant capacity (IC₅₀ = 1.5 µg/mL). Additionally, the EAE of G. gaudichaudii was effective against Gram-positive bacteria with minimal inhibition concentration (MIC) of 15.625–25 µg/mL whereas ME of G. planchonii was effective against both Gram-positive bacteria (MIC = 160 µg/mL) and Gram-negative bacteria (MIC = 75 µg/mL).

Conclusion

Several extracts of Garcinia species demonstrated valuable antioxidant and antimicrobial properties.

Phytochemical characterization, and antioxidant and antibacterial activities of the hydroethanolic extract of Anadenanthera peregrina stem bark

The Brazilian Cerrado biome consists of a great variety of endemic species with several bioactive compounds, and Anadenanthera peregrina (L.) Speg is a promising species. In this study, we aimed to perform phytochemical characterization and evaluate the antioxidant and antibacterial activities against Staphylococcus aureus and Escherichia coli of the hydroethanolic extract of A. peregrina stem bark. The barks were collected in the Botanical Garden of Goiânia, Brazil. The hydroethanolic extract was obtained by percolation and subjected to physicochemical screening, total phenolic content estimation, high-performance liquid chromatography (HPLC) fingerprinting, and antioxidant (IC50 values were calculated for the 2,2-diphenyl-1-picrylhydrazyl assay - DPPH) and antibacterial activity determination. The pH of the extract was 5.21 and density was 0.956 g/cm3. The phytochemical screening indicated the presence of cardiac glycosides, organic acids, reducing sugars, hemolytic saponins, phenols, coumarins, condensed tannins, flavonoids, catechins, depsides, and depsidones derived from benzoquinones. The extract showed intense hemolytic activity. The total phenolic content was 6.40 g GAE 100 g-1. The HPLC fingerprinting analysis revealed the presence of gallic acid, catechin, and epicatechin. We confirmed the antioxidant activity of the extract. Furthermore, the extract did not inhibit the growth of E. coli colonies at any volume tested, but there were halos around S. aureus colonies at all three volumes tested. These results contribute to a better understanding of the chemical composition of A. peregrina stem bark and further support the medicinal applications of this species.

In vivo Anti-Plasmodium Activity and Toxicity of Afzelia bipindensis and Senna Siamea Extracts: A Murine Model

Background:

Malaria, a parasitosis affecting man, remains a public health problem in developing countries where morbidity and mortality are very high. Afzelia bipindensis and Senna siamea are two plants used in the treatment of malaria in different African countries including Cameroon.

Objective:

The aim of the present study was to evaluate the antiplasmodial activity of hydroethanolic leaves extracts of Afzelia bipindensis and Senna siamea, from Northern Cameron using Plasmodium berghei and to investigate the acute and sub-acute toxicity of leaves extracts in a rodent model.

Methods:

The four days Peter’s suppressive test was used to evaluate the antiplasmodial activity and the OCDE 423 and 412 guidelines were applied to evaluate acute and sub-acute toxicity. Biochemical tests related to hepatic, cardiac and renal toxicity were also assessed.

Results:

The leaves’ extracts of Afzelia bipindensis at doses 180, 360, 720 mg/kg and Senna siamea at doses of 100, 200, 400 mg/kg have shown significant antiplasmodial activity (P) with parasite reduction ≈ 50%. No mortality of rats was observed at the tested doses. The biochemical analysis did not reveal any statistically significant difference when compared with control. However, ALT was statistically increased at a higher dose (720 mg/kg) of Afzelia bipindensis leaves extract. On the other hand, there was a significant decrease in triglycerides at 360 mg/kg and 720 mg/kg

Conclusion:

It is concluded that daily consumption of leaves extract of Afzelia bipindensis and Senna siamea are without significant risks to human health, favoring the use of these products in the treatment of malaria.