tormentic acid
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2021 ◽  
Vol 2021 ◽  
pp. 1-13
Author(s):  
Chido Bvumbi ◽  
Godloves Fru Chi ◽  
Marc Y. Stevens ◽  
Molly Mombeshora ◽  
Stanley Mukanganyama

Candida albicans and Candida tropicalis are the leading causes of human fungal infections worldwide. There is an increase in resistance of Candida pathogens to existing antifungal drugs leading to a need to find new sources of antifungal agents. Tormentic acid has been isolated from different plants including Callistemon citrinus and has been found to possess antimicrobial properties, including antifungal activity. The study aimed to determine the effects of tormentic and extracts from C. citrinus on C. albicans and C. tropicalis and a possible mode of action. The extracts and tormentic acid were screened for antifungal activity using the broth microdilution method. The growth of both species was inhibited by the extracts, and C. albicans was more susceptible to the extract compared to C. tropicalis. The growth of C. albicans was inhibited by 80% at 100 μg/ml of both the DCM: methanol extract and the ethanol: water extract. Tormentic acid reduced the growth of C. albicans by 72% at 100 μg/ml. The effects of the extracts and tormentic acid on ergosterol content in C. albicans were determined using a UV/Vis scanning spectrophotometer. At concentrations of tormentic acid of 25 μg/ml, 50 μg/ml, 100 μg/ml, and 200 μg/ml, the content of ergosterol was decreased by 22%, 36%, 48%, and 78%, respectively. Similarly, the DCM: methanol extract at 100 μg/ml and 200 μg/ml decreased the content by 78% and 88%, respectively. A dose-dependent decrease in ergosterol content was observed in cells exposed to miconazole with a 25 μg/ml concentration causing a 100% decrease in ergosterol content. Therefore, tormentic acid inhibits the synthesis of ergosterol in C. albicans. Modifications of the structure of tormentic acid to increase its antifungal potency may be explored in further studies.


Molecules ◽  
2021 ◽  
Vol 26 (13) ◽  
pp. 3797
Author(s):  
Marta Olech ◽  
Wojciech Ziemichód ◽  
Natalia Nowacka-Jechalke

This review focuses on the natural sources and pharmacological activity of tormentic acid (TA; 2α,3β,19α-trihydroxyurs-2-en-28-oic acid). The current knowledge of its occurrence in various plant species and families is summarized. Biological activity (e.g., anti-inflammatory, antidiabetic, antihyperlipidemic, hepatoprotective, cardioprotective, neuroprotective, anti-cancer, anti-osteoarthritic, antinociceptive, antioxidative, anti-melanogenic, cytotoxic, antimicrobial, and antiparasitic) confirmed in in vitro and in vivo studies is compiled and described. Biochemical mechanisms affected by TA are indicated. Moreover, issues related to the biotechnological methods of production, effective eluents, and TA derivatives are presented.


Molecules ◽  
2020 ◽  
Vol 25 (22) ◽  
pp. 5443
Author(s):  
Sophie Hoenke ◽  
Immo Serbian ◽  
Hans-Peter Deigner ◽  
René Csuk

The combination of the “correct” triterpenoid, the “correct” spacer and rhodamine B (RhoB) seems to be decisive for the ability of the conjugate to accumulate in mitochondria. So far, several triterpenoid rhodamine B conjugates have been prepared and screened for their cytotoxic activity. To obtain cytotoxic compounds with EC50 values in a low nano-molar range combined with good tumor/non-tumor selectivity, the Rho B unit has to be attached via an amine spacer to the terpenoid skeleton. To avoid spirolactamization, secondary amines have to be used. First results indicate that a homopiperazinyl spacer is superior to a piperazinyl spacer. Hybrids derived from maslinic acid or tormentic acid are superior to those from oleanolic, ursolic, glycyrrhetinic or euscaphic acid. Thus, a tormentic acid-derived RhoB conjugate 32, holding a homopiperazinyl spacer can be regarded, at present, as the most promising candidate for further biological studies.


2020 ◽  
Vol 2020 ◽  
pp. 1-14
Author(s):  
Tafadzwa Chipenzi ◽  
Genuine Baloyi ◽  
Tatenda Mudondo ◽  
Simbarashe Sithole ◽  
Godloves Fru Chi ◽  
...  

ESKAPE pathogens, namely, Enterococcus faecium, Staphylococcus aureus, Klebsiella pneumoniae, Acinetobacter baumannii, Pseudomonas aeruginosa, and Enterobacter species, are responsible for a majority of all healthcare-acquired infections (HAI). The bacteria cause nosocomial infections in immunocompromised patients. Extracts from Callistemon viminalis have been shown to have antibacterial, antifungal, and anti-inflammatory activities. Tormentic acid congener, a pentacyclic triterpene saponin, was isolated from C. viminalis leaves. This study aimed to investigate the antibacterial effects of tormentic acid congener and leaf extracts on biofilm formation by A. baumannii, S. aureus, S. pyogenes, and P. aeruginosa. The antibacterial effects were determined by the microbroth dilution method, and ciprofloxacin was used as the standard antibacterial drug. Biofilm formation and detachment assays were performed using crystal violet staining. Production of extracellular polymeric DNA and polysaccharides from biofilms was also determined. Tormentic acid congener showed time-dependent antibacterial activity against P. aeruginosa with a MIC of 100 µg/ml and caused significant protein leakage. Antibacterial activity was found when tormentic acid congener was tested against both S. aureus and P. aeruginosa. The MICs were found to be 25 µg/ml and 12.5 µg/ml for P. aeruginosa and S. aureus cells, respectively. S. pyogenes was found to be susceptible to tormentic acid congener and the hydroethanolic extract with an MIC of 100 µg/ml and 25 µg/ml, respectively. A. baumannii was found not to be susceptible to the compound or the extracts. The compound and the extracts caused a significant decrease in the biofilm extracellular polysaccharide content of S. pyogenes. The extracts and tormentic acid congener caused detachment of biofilms and decreased the release of extracellular DNA and capsular polysaccharides from biofilms of P. aeruginosa and S. aureus. Tormentic acid congener and extracts, thus, have significant antibacterial and antibiofilm activities on these selected ESKAPE bacteria and can act as source lead compounds for the development of antibacterial triterpenoids.


2020 ◽  
Vol 15 (7) ◽  
pp. 1934578X2093493
Author(s):  
Jingxin Chen ◽  
Lin Ni ◽  
Yao Zhang ◽  
Yingsa Zhu ◽  
Wei Huang ◽  
...  

A new ellagic acid derivative 3,3′-di- O-methylellagic acid 4 ′-α-l-arabinopyranoside (1), with 9 known compounds identified as 3,3′-di- O-methylellagic acid (2), 3,3′-di- O-methylellagic acid 4′-α-d-arabinofuranoside (3), 3,3′-di- O-methylellagic acid 4′ -β-d-glucopyranoside (4), 3,3′-di- O-methylellagic acid 4 ′-β-d-xylopyranoglucoside (5), 3,3′,4-tri- O-methylellagic acid 4′-β-d-glucopyranoside (6), tormentic acid (7), ursolic acid (8), euscaphic acid (9), and betulinic acid (10), was isolated from the twigs of Euscaphis konishii Hayata. Compounds 1, 3, and 5 to 7 were isolated from this plant for the first time, and compounds 1 and 5 were obtained from the plant genus for the first time. The structure of the new compound was confirmed by HRESIMS, NMR, and compared with data from the literature . The cytotoxicities of 10 isolated compounds were tested, with compounds 1 to 6 showing moderately inhibited activity against the Human Hepatocarcinoma cell line (HepG2 cells) with an IC50 value ranging from 69.7 to 181.8 μM.


2020 ◽  
Vol 2020 ◽  
pp. 1-6
Author(s):  
Rumbidzai Mashezha ◽  
Molly Mombeshora ◽  
Stanley Mukanganyama

Staphylococcus aureus is among the common nosocomial pathogens. Antibiotics have been used to treat S. aureus infections. However, there has been increased mortality associated with drug-resistant strains of S. aureus. Extracellular proteases have been implicated to be responsible for the transition of S. aureus from an adhesive pathogen to an invasive pathogen. The development of resistant strains has necessitated the search for new sources of drugs. Plants have been traditionally used as sources of therapeutic molecules. The objective of this study was to determine the effect of tormentic acid and the extracts from Callistemon citrinus on the production of extracellular proteases by S. aureus. The broth microdilution antibacterial susceptibility assay was used to determine the antibacterial effects of tormentic acid and the extracts on S. aureus. Both extracts showed a minimum inhibitory concentration (MIC) value of 50 μg/ml. The water : ethanol (50 : 50) and the dichloromethane : methanol (50 : 50) extracts were found to be bactericidal against S. aureus at a concentration of 100 μg/ml and 50 μg/ml, respectively. The effect of tormentic acid and extracts on extracellular protease production was investigated using the protease assay. A zone of proteolytic activity (Pr) was measured as the ratio of the diameter of the colony to the total diameter of colony plus zone of hydrolysis. The extracts reduced the production of extracellular proteases, while tormentic acid completely inhibited the production of extracellular proteases by S. aureus. The Pr value for tormentic acid was found to be 1. The Pr values of the dichloromethane : methanol extract and the water : ethanol extract were 0.92 and 0.84, respectively. In conclusion, tormentic acid was shown to inhibit extracellular protease production; therefore, there is need to explore its use in antivirulence therapy to combat S. aureus infections.


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