Inhibition of HIV‐1 Protease by Carpobrotus edulis (L.)

Abstract

Carpobrotus edulis (L.) is a plant commonly found in the Eastern Cape Province of South Africa and is used for the general treatment of infections relating to the human immunodeficiency virus (HIV). HIV-1 protease plays an important role during HIV replication and maturation to its infectious form, and therefore inhibition of the enzyme is one of the main focus areas in drug development. The inhibitory effect of a water extract of C. edulis leaves against HIV-1 protease activity was determined using the SensoLyte® 520 HIV-1 protease assay fluorimetric kit and employing a HiLyte Fluor™488/QXL™520 fluorescence resonance energy transfer (FRET) peptide. Cytotoxicity of the extract towards HeLa Chang cell lines was determined using an in vitro MTT assay, and the phytochemical profile of the extract was determined with FT-IR and LC-MS. HIV-1 protease activity was inhibited 83.06% (IC50 1.6 mg/ml) (p<0.0001) by the pepstatin A inhibitor control. Treatment with all C. edulis extract concentrations (16, 1.6, 0.16, and 0.016 mg/ml) inhibited HIV-1 protease activity significantly (p<0.0001) in a typical dose response manner. With regards to cytotoxicity, the negative controls containing untreated HeLa Chang cells exhibited high formazan formation rates in contrast with the positive controls, containing curcumin, which reduced formazan formation significantly (p<0.001), exhibiting cytotoxicity towards the cells. There was no significant (p>0.05) difference in the formazan formation rates between the negative controls and 1, 0.5, 0.125, 0.065, 0.031, and 0.015 mg/ml plant extract, confirming no toxicity of C. edulis extracts towards HeLa Chang cells. Major functional phytochemical compounds identified included alcohols, phenols, alkanes, amines, carboxylic acids, and esters. LC-ESI-TOF/MS analysis revealed the putative identities of main compounds present in the aqueous leaves extract, including some that contribute to its anti-HIV-1 protease action.

Developments in Exploring Fungal Secondary Metabolites as Antiviral Compounds and Advances in HIV-1 Inhibitor Screening Assays

“…Developing these replication assays to represent all possible target sites in the HIV-1 genome will allow for rapid and unbiased screening of natural microbial products against various targets and save costs and time for hit identification [64,65]. Furthermore, full replication assays will also provide insight into protein-protein interactions, and thus increase the early small molecular compound screening capacity for future viral inhibitors [61,[66][67][68][69][70][71][72][73][74][75][76]. The fungal kingdom presents a great source of small therapeutic compounds with…”

Phytochemical screening and in vitro antioxidant activity analysis of leaf and callus extracts of Allophylus serratus (ROXB) KURZ.

“…These phytochemicals compounds present in the leaf and callus extracts are responsible for many biological activities (34).The presence of these phytochemicals strengthens the traditional use of the plant A. Serratus have medicinal value. The presence of alkaloids, saponins and tannins in plants play very important role in pharmaceutical field as reported (35). These compounds have various antibiotic properties and they are used in treating diseases caused by common pathogenic strains.…”

From Tradition to Health: Chemical and Bioactive Characterization of Five Traditional Plants

“…In Africa, this species has been used in the folk treatment of human immunodeficiency virus infections, dysentery, skin wounds, throat infections, or digestive problems, among others [ 22 , 23 ]. Several studies have reported the antioxidant, antiproliferative, antimicrobial and antiviral activities of this plant [ 24 , 25 , 26 ].…”