Potent bioactive metabolites from Olea ferruginea

Seven known (1-7) and one new compound (8) were isolated and identified from the stem of Olea ferruginea. The species has been recognised as a new source for six of the known metabolites (1, 3, 4, 5, 6, and 7). Based on detailed spectroscopic analyses, these compounds were identified as scopoletin (1), 8-ketosetosterol (2), (+)-cycloolivil (3), (+)-africanal (4), isovanilic acid (5), hydroxytyrosol acetate (6), vanillic acid (7), and cycloolivil A (8). The crude extracts and purified compounds were analysed for their Leishmanicidal, anti-glycation, anti-cancer, and anti-inflammatory activities. n-Hexane fraction was found to be the most active (among all the fractions), against Leishmania parasites, exhibiting 97.85% inhibition at 15 μg/mL. However, none of the extracts showed any significant anti-glycation or anti-cancer potential, all the fractions, except the aqueous layer, displayed moderate to low anti-inflammatory activity. Compound 1 was found to have strong anti-inflammatory activity, exhibiting 96.7% stimulation at 25 μg/mL.

In vitro anti-inflammatory, antidiabetic, antibacterial, and in silico studies of Ferruginan A isolated from Olea ferruginea Royle (Oleaceae)

Objective

Traditionally, Olea ferruginea Royle (Oleaceae) has been used as a painkiller and antidiabetic in various ailments. To provide a scientific background to this folklore the current study was designed to anti-inflammatory and antidiabetic effects of one of the isolated compound from this plant.

Methods

Ferruginan A was isolated from the ethyl acetate extract of Olea ferruginea bark. This isolated molecule was subjected to in-vitro anti-inflammatory and antidiabetic effects using HRBCs and glucose uptake tests. The compound was also tested for molecular docking and ADMET study.

Results

Regarding the anti-inflammatory effect, the tested compound demonstrated a 69.82 % inhibition at a concentration of 100 µg/mL, while the Ferruginan A (100 µl/mL) increased the uptake of glucose (3.79-71.86 %) in the yeast cell. Similarly, the zone of inhibition values of Ferruginan A (24.98 mm) against Escherichia coli were found to be comparable to standard (Imipenem: 31.09 mm). The mechanism of antidiabetic and anti-inflammatory effects was explored by using docking simulations performed on four molecular targets related to diabetes and inflammation. The results showed that the isolated compound may act as an antidiabetic agent by inhibiting the 5' Adenosine monophosphate-activated protein kinase (AMPK). While it also showed inhibition of anti-inflammatory targets COX-1, COX-2, and Tumor necrosis factor alpha (TNF-α). The ADMET prediction study revealed that isolated compound possesses favorable ADMET profile.

Conclusion

It was concluded that Ferruginan A might be a significant anti-inflammatory and antidiabetic molecule.

The complete chloroplast genome sequence of Olea ferruginea

The first complete chloroplast genome sequences of Olea ferruginea were reported in this study. The cpDNA of O. ferruginea is 155,531 bp in length, contains a large single-copy region (LSC) of 86,279 bp and a small single-copy region (SSC) of 17,790 bp, which were separated by a pair of inverted repeat (IR) regions of 25,731 bp. The genome contains 129 genes, including 84 protein-coding genes, 8 ribosomal RNA genes, and 37 transfer RNA genes. The overall GC content of the whole genome is 37.8%. Phylogenetic analysis of six chloroplast genomes within the genus Olea suggests that O. ferruginea is closely related to Olea europaea subsp. cuspidate.

Spectroscopic and density functional theory studies of 5,7,3',5'-tetrahydroxyflavanone from the leaves of Olea ferruginea

5,7,3',5'-Tetrahydroxyflavanone (1) was isolated from the leaves of Olea ferruginea and a theoretical model was developed for obtaining the electronic and spectroscopic properties of 1. The geometric and electronic properties were calculated at B3LYP/6-311 G (d, p) level of Density Functional Theory (DFT). The theoretical data was in good agreement with the experimental one. The optimized geometric parameters of compound 1 were calculated for the first time. The theoretical vibrational frequencies of 1 were found to correlate with the experimental IR spectrum after a scaling factor of 0.9811. The UV and NMR spectral data computed theoretically were in good agreement with the experimental data. Electronic properties of the compound i.e., ionization potential (IP), electron affinity (EA), coefficients of HOMO and LUMO were estimated computationally for the first time which can be used to explain its antioxidant as well as other related activities and more active sites on it. The intermolecular interactions and their effects on IR frequencies, electronic and geometric parameters were simulated using water molecule as a model for hydrogen bonding with flavonoid hydroxyl groups.