Records of Natural Products Articles

Antibiotic resistance had first been reported not long after the discovery of the first antibiotic and has remained a major public health issue ever since. Challenges are constantly encountered during the mitigation process of antibiotic resistance in the clinical setting; especially with the emergence of the formidable superbug, a bacteria with multiple resistance towards different antibiotics; this resulted in the term multidrug resistant (MDR) bacteria. This rapid evolution of the resistance phenomenon has propelled researchers to continuously uncover new antimicrobial agents in a bid to hopefully, downplay the rate of evolution despite a drying pipeline. Recently, there has been a paradigm shift in the mining of potential antimicrobials; in the past, targets for drug discovery were from microorganisms and at current, the focus has moved onto plants, this is mainly due to the beneficial attributes that plants are able to confer over that of microorganisms. This review will briefly discuss antibiotic resistance mechanisms employed by resistant bacteria followed by a detailed expository regarding the use of secondary metabolites from plants as a potential solution to the MDR pathogen. Finally, future prospects recommending enhancements to the usage of plant secondary metabolites to directly target antibiotic resistant pathogens will be discussed.

Two new aromatic compounds, phillipsins A (1) and B (2) were isolated from the Bornean wild ginger Zingiber phillippsii Mood & Theilade, and were characterized based on spectroscopic data (HRESI-MS, FTIR as well as 1D and 2D NMR). These metabolites also exhibited strong antifungal activity against selected fungi.

The fatty acid, tocopherol, and sterol contents of the extracted seed oils from three Garcinia species, including G. hanburyi Hook. f., G. multiflora Champ. ex Benth., and G. gaudichaudii Planch. & Triana, were analyzed. The results showed that the Garcinia seeds contained a high amount of oil (16.28–29.91%). The major monounsaturated and saturated fatty acids were oleic acid (82.97 % in G. multiflora and 45.37 % in G. hanburyi) and stearic acid (58.87 % in G. gaudichaudii and 50.12 % in G. hanburyi). In addition, three extracted oils exhibited moderate antioxidant activity with G. hanburyi displayed the strongest activity with IC 50 value of 6.34± 0.43 μg /mL or EC 50 = 11.71 ± 0.22 μg /mL.

An efficient method for the screening and isolation of potent antioxidants from a tibetan medicinal plant by employing online HPLC–DPPH assay combined HSCCC has been successfully established. Six major constituents : boschnaloside ( 1 ), alyssonoside ( 2 ), leucosceptoside A ( 3 ), isoverbascoside ( 4 ), leucosceptoside B ( 5 ) and verbascoside ( 6 ) were isolated and purified from the water extract by HSCCC using ethyl acetate-n-butanol-water as two-phase solvent system. The results indicated that the combination of the online HPLC–DPPH assay with HSCCC could be suitable for the screening and separation of antioxidant compounds from extract of this plant or other medicine plants.

Finding non-invasive skin depigmenting agentsrepresent an important goal of cosmetic research and industry. It is now admited that Tyrosinase inhibitor substances could be the most efficient molecules in this field because Tyrosinase is the key enzyme in the melanogenesis process. In the pathology of macular skin hyperpigmentations it can mention aesthetic problems such as: melasma gravidarum, pigmentation of aged skin, photosensibilisation, hepatic disfunctions and post-inflammatory residual pigmentation. The aim of the study was to find out if the Lavandula essential oil has depigmenting properties on human skin, having as theoretical premise its tyrosinase-blocking effect, previously reported in literature for some plant species. By using gas chromatograph coupled with mass spectrometer (GC/MS), a pharmaceutical cream preparation, a protocol of exploration on volunteers (including criteria) and a mexameter, we have highlighted the composition of a sample of Lavandula angustifolia essential oil (LEO) and its depigmenting effect on skin melanic macula. The results highlightes that the main compounds identified were linalool ( 26.783%), terpinen-4-ol (22.143%) and 3-carene (21.668%), Terpinen-4-ol is represented as the possible active compound in tyrosinase inhibition. Our dermocosmetic assay shows that the depigmenting effect of Lavandula angustifolia oil is effective after 2 months of daily topical treatement, when the melanine average value (measured by the mexameter) decreases more than a third from the innitial value. The study remarks that Lavandula angustifolia essential oil (LEO) in daily cutaneous pharmaceutical form application, during two month, reduces the intensity of spot skin melanin, exprimed through mexametric values.

Luteolin , which is structurally classified under the flavonoids, is naturally distributed abundant among medicinal plants, vegetables and fruits. The wound healing effects of Luteolin ointments were evaluated for incision and excision wound models on non-diabetic and Streptozotocin induced diabetic rats by using macroscopical, biomechanical, biochemical and histopathological methods. Two different concentrations (0.5 % and 1 % (w/w)) of the Luteolin ointment were prepared with the mixture of glycol stearate:propylene glycol:liquid paraffin (3:6:1) and 0.5 g of the ointments were applied topically on wounds once daily for 7 and 14 days. During the experiments, wounds were visually observed, photographically documented and wound areas were measured. After 7 and 14 days treatment, animals were sacrificed under anesthesia and hydroxyproline measurement and biomechanical analysis were performed. Histopathology of the wound area was evaluated considering features of re-epithelialization, thickness of the granulation tissue, angiogenesis, presence of inflammation, number of mast cells. Outcomes of this study revealed that Luteolin ointments improved wound healing process of skin tissue both in non-diabetic and diabetic wounds. The best wound healing activity was observed in incision and excision wounds (97.6 %, 96.1 %, respectively) treated with 0.5 % (w/w) Luteolin ointment on day 14 according to macroscopic results.

Honeysuckle or Lonicera etrusca is one of the important medicinal-plants that is traditionally-used as a potential antioxidant. The aim of this work was to make a phytochemical-evaluation of Lonicera etrusca ultrasound-assisted spray-dried extract versus conventional-method utilizing RP-HPLC aided-method in the potential management of diabetes. Ultrasound-assisted spray-drying (US-SD) is a new productive-technique aiming at increasing the efficiency and extract-yield in addition to short time of exposure to elevated temperature thus improving product stability. A bio-guided study utilizing RP-HPLC, 1H and 13C NMR methods indicated that the most active antidiabetic-compound was isochlorogenic acid (ICA). Diabetes measurement utilizing glucometers and HbA1c methods was applied. Serum-insulin levels and serum-catalase (CAT) was also monitored. The US-SD preserved time by 4 folds and with higher yield (ca. 20%) than the conventional method. The US-SD also had higher quality in US-SD honeysuckle (HS-sd) constituents than the conventional method as supported by RP-HPLC analysis. Rotary evaporated honeysuckle (HS-r) major peaks identified were; chlorogenic acid (38.6%), caffeic acid (5.8%), isochlorogenic acid (36.1%), luteolin-7-O-glucoside (3.3%), and quercetin (3.0%). HS-sd major peaks identified were; chlorogenic acid (40.5%), caffeic acid (6.4%), isochlorogenic acid (43.3%), luteolin-7-O-glucoside (3.5%), and quercetin (3.2%). HS-sd had significant (p˂0.05, n=7/group) antidiabetic-activity more than HS-r. HS-sd had more-significant dose-dependent increase in serum-insulin, CAT-levels and body-weights more prominent than HS-r. Compared to conventional-methods, US-SD has shown to be time-conserving, efficient, and active-ingredients preserving method. The antidiabetic-potentials of HS-sd and ICA were probably mediated via the significant insulin-secretagogue effect and the attenuation glucose-provoked oxidative-stress.

Phytochemical investigation of Lycium shawii Roem. & Schult provided fourteen compounds, including lyciumate (1), dehydrocostus lactone (2), costunolide (3), catechin(4), lyciumaside (5), emodin (6), emodin-8-O-β- D -glucoside (7), aloe-emodin (8), aloe-emodin-8-O-β- D -glucoside (9), aloe emodin-11- O -rhamnoside (10 ) , chrysophanol - 8 - O -β- D - glucoside (11), nonacosane-10-ol (12), betulinic acid (13) and β -sitosterol glucopyranoside (14). The compounds may be classified as three sesquiterpene lactones (1-3), two phenolic compounds (4 and 5), six anthraquinones (6-11), one long chain alcohol (12), one lupane-type triterpenoid (13) and a steroid (14). Compounds 2, 3, 7 and 9-12 are reported here for the first time as isolated from any species of Lycium as well as from the Solanaceae family while compounds 8, 13 and 14 are reported to be found for the first time in the genus Lycium. All structural assignments were made by comparing the NMR spectral data of the pure isolates with that published in the quoted literature.

Salvia macilenta Boiss. is a fragrant subshrub which grows wild in some regions of Iran. In this work, we contrasted essential oil contents and components of two wild populations under two different ecological situations (Kerman and Baluchistan Provinces, Center and South East of Iran, respectively). For the first time the antibacterial and the antimycotic properties of these essential oils were also evaluated against seven bacterial and fungal strains. The essential oils were isolated by hydrodistillation method and the chemical compositions of the samples were examined by GC and GC-MS. Kerman (K) specimen was found to be rich in α -pinene (29.0%), p-cymene (10.7%), veridiflorol (9.1%), α-eudesmol (8.7%), bornyl acetate (7.3%) with lesser concentrations of borneol (4.9%) . Principal components were identified as α -eudesmol (35.6%), α-pinene (7.7%), bornyl acetate (7.6%), ( E )-nerolidol (6.5%) and veridiflorol (5.9%) from Baluchistan (B) sample. Oxygenated sesquiterpenes were found to be the principal class of components in the oil of Baluchistan sample (53.0%) whereas monoterpene hydrocarbons were the main class in Kerman specimen (46.6%). The results demonstrated that the variety in the volatile compounds could be considered as chemotaxonomic importance and it may be ascribed to their different ecological and geographical source.

Five known flavonoid glycosides namely, juglanin (1), astragalin (2), nicotiflorin (3), isoquercetin (4) and apigenin-7-O- b -glucuronide (5), and a phenolic glucoside, arbutin (6), were isolated for the first time from the leaves of Afgekia mahidolae (Fabaceae). Their structures were elucidated using one- and two-dimensional NMR spectroscopic methods and comparison with the literature. The ability of 1-4 to promote the migration of CCD-1064sk fibroblasts into a scratch-wound area was evaluated. The results indicated that juglanin (1) and nicotiflorin (3) significantly increased the migration of these cells and, hence, supporting the wound healing effect of flavonol glycosides.

Flaxseed (Linum usitatissimum L.) is important source of oil and protein for industrial, pharmaceutical, and nutritional applications. In order to estimate the effects of lyophilized aqueous extract of flaxseed shell (AEF) and evaporated ethanolic extract of flaxseed shell (EEF), we studied their DPPH, ABTS, DMPD and O 2 •- scavenging effects. Total antioxidant activity by ferric thiocyanate method, Fe 3+, Cu 2+ and [Fe 3+-(TPTZ) 2] 3+ reducing ability, and Fe 2+ chelating activity. Also, α-tocopherol, BHA, trolox, and BHT were used as positive controls. The results clearly AEF and EEF demonstrated effective antioxidant activity. The quantity of p-hydroxybenzoic, vanillin, p-coumaric acid, ascorbic acid, ferulic acid, and ellagic acid were investigated by LC-MS/MS. The present study will introduce a novelty for further studies on the antioxidant effects of AEF and EEF.