Anti-HIV Activity of Ocimum labiatum Extract and Isolated Pheophytin-a

Phytochemical analysis on the aerial parts of Teucrium capitatum L. with aspects of chemosystematics and ethnobotany

The phytochemical analysis on the aerial parts of Teucrium capitatum L. collected from a new population in Central Italy, led to the identification of eight compounds, i.e. pheophytin a (1), poliumoside (2), apigenin (3), luteolin (4), cirsimaritin (5), cirsiliol (6), 8-O-acetyl-harpagide (7) and teucardoside (8) belonging to four different classes of secondary metabolites. Pheophytin a (1) represents a newly identified compound in the genus whereas compounds (7-8) are newly identified compound in the species. The chemotaxonomic and ethnobotanical aspects relative to the presence of these compounds were widely discussed suggesting important conclusions for both.

Efficacy in degradation of carcinogenic pollutant sulforhodamine B by green synthesized silver nanoparticles

Colloidal Silver nano-particles were grown at room temperature using leaf extract of Ocimum tenuiflorum. The silver nanoparticles suspended in the solution were found to be stable for over a period of 2 months. Structural, optical and photo catalytic behavior of the suspended silver (Ag) nano-particles (NPs) was characterized. From TEM analysis the size of the silver nanoparticles was estimated to be 25–30 nm. Our findings suggest that the ratio between the molarity of AgNO3 and the volume of leaf extract does not have any role in controlling the size of the Ag nano-particles. These green synthesized Ag nano-particles exhibit degradation of the carcinogenic organic pollutant sulforhodamine B in absence of light.

Hydroalcoholic extract of Tagetes minuta L. inhibits inflammatory bowel disease through the activity of pheophytins on the NF-κB signalling pathway

ETHNO-PHARMACOLOGICAL RELEVANCE

Species of the genus Tagetes are well known for their anti-inflammatory properties. Tagetes minuta "Huacatay" is an endemic species of South America that has been used in traditional medicine since ancient times as a remedy for stomach and intestinal discomfort.

AIM OF THE STUDY

The aim of this study is to investigate the anti-inflammatory activity of the aqueous and hydroalcoholic extracts of the Huacatay, identifying the compounds responsible for this activity.

MATERIALS AND METHODS

Anti-inflammatory activity of the compounds, fractions and extracts was evaluated in Hs 746T (stomach), HIEC-6 (intestine) and THP-1 (monocytes peripheral blood) cells by measuring their inhibitory capacity against the NF-κB production.

RESULTS

Aqueous and hydroalcoholic extracts of Tagetes minuta displayed anti-inflammatory activity in vitro, the hydroalcoholic extract being the most active (IC₅₀ between 59.72 and 66.42 μg/mL) in all cell lines. Bio-guided hydroalcoholic extract fractionation led to the isolation and characterisation of two pheophytins, pheophytin a (1) and 13²-hydroxy pheophytin a (2). Both compounds inhibited the production of NF-κB with IC₅₀ values in the low micromolar range, with an IC₅₀ between 12.32 and 16.01 μM for compound 1 and 7.91-9.87 μM for compound 2.

CONCLUSIONS

The two pheophytins isolated in this study inhibit the production of NF-κB, thus showing that the traditional anti-inflammatory use of Tagetes minuta can be proved through pharmacological assays. This contributes to understanding the anti-inflammatory activity of the Huacatay extracts and their use in the treatment of stomach and intestinal discomfort.

The Potential of Natural Diterpenes Against Tuberculosis: An Updated Review

Every year, 10 million people are affected by tuberculosis (TB). Despite being a preventable and curable disease, 1.5 million people die from TB each year, making it the world's top infectious disease. Many of the frontline antibiotics cause painful and disagreeable side effects. To mitigate the side effects from the use of chemically synthesized or clinical anti-tubercular drugs, there are many research studies focussed on natural products as a source of potential anti-tuberculosis drugs. Among different phytoconstituents, several classes of diterpenoids exert significant antimicrobial effects. This review explores diterpenoids as potential anti-tubercular drugs from natural sources. A total of 204 diterpenoids isolated from medicinal plants and marine species are discussed that inhibit the growth of Mycobacterium tuberculosis. The literature from 1994-2018 is reviewed, and 158 diterpenoids from medicinal plants, as well as 40 diterpenoids from marines, are alluded to have antituberculosis properties. The antitubercular activities discussed in the review indicate that the type of diterpenoids, the Mtb strains, substituents attached to diterpenoids and their position in the diterpenoids general skeleton can change the compounds antimycobacterial inhibitory effects.

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

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.

Structure-Activity-Relationship and Mechanistic Insights for Anti-HIV Natural Products

Acquired Immunodeficiency Syndrome (AIDS), which chiefly originatesfroma retrovirus named Human Immunodeficiency Virus (HIV), has impacted about 70 million people worldwide. Even though several advances have been made in the field of antiretroviral combination therapy, HIV is still responsible for a considerable number of deaths in Africa. The current antiretroviral therapies have achieved success in providing instant HIV suppression but with countless undesirable adverse effects. Presently, the biodiversity of the plant kingdom is being explored by several researchers for the discovery of potent anti-HIV drugs with different mechanisms of action. The primary challenge is to afford a treatment that is free from any sort of risk of drug resistance and serious side effects. Hence, there is a strong demand to evaluate drugs derived from plants as well as their derivatives. Several plants, such as Andrographis paniculata, Dioscorea bulbifera, Aegle marmelos, Wistaria floribunda, Lindera chunii, Xanthoceras sorbifolia and others have displayed significant anti-HIV activity. Here, weattempt to summarize the main results, which focus on the structures of most potent plant-based natural products having anti-HIV activity along with their mechanisms of action and IC50 values, structure-activity-relationships and important key findings.

Chemical constituents from the leaves of Elaeocarpus floribundus

The genus Elaeocarpus belongs to the Elaeocarpaceae family, consists of about 350 species distributed in the tropical and subtropical regions. Plants in the genus, reportedly, contain compounds known for various biological activities like affinity for the δ-opioid receptor, antioxidant, cytotoxicity and antimicrobial activities. Elaeocarpus floribundus, commonly known in India as 'Indian Olive' is a medicinal plant widely distributed through Eastern Asia and the pacific. Here, we report the isolation and spectroscopic characterization of fifteen compounds (1-15) and additional three compounds (16-18) were obtained as mixtures. This includes four fatty acids, three diterpenoids, one triterpene alcohol, two fatty alcohols, three phaeophytins, one phytosterol, one sesquiterpene, and three hydrocarbons from the hexane extract of the leaves. Compounds 1-18 are reported for the first time from this source. To the best of our knowledge, this is an initial report of the isolation of compounds 1-11, and 14-18 from the genus Elaeocarpus.