Withania frutescens L. is a wild perennial woody plant used by the local population for diverse therapeutic purposes. This work aims to study for the first time the potential inhibitory effect of this plant hydroethanolic extract on α-amylase and α-glucosidase activities using in vitro methods and its antidiabetic and antihyperglycemic activities using alloxan-induced diabetic mice as a model for experimental diabetes. Two doses were selected for the in vivo study (200 and 400 mg/kg) and glibenclamide, a well-known antidiabetic drug (positive control) in a subacute study (28 days) where the antihyperglycemic activity was also assessed over a period of 12 h on diabetic mice. The continuous treatment of diabetic mice with the extract of Withania frutescens for 4 weeks succeeded to slowly manage their high fasting blood glucose levels (after two weeks), while the antihyperglycemic test result revealed that the extract of this plant did not control hyperglycemia in the short term. No toxicity signs or death were noted for the groups treated with the plant extract, and it shows a protective effect on the liver and kidney. The in vitro assays demonstrated that the inhibition of alpha-amylase and alpha-glucosidase might be one of the mechanisms of action exhibited by the extract of this plant to control and prevent postprandial hyperglycemia. This work indicates that W. frutescens have an important long term antidiabetic effect that can be well established to treat diabetes.

Coriandrum sativum L. seeds are traditionally used to treat diabetes and its complications (inflammation and formation of reactive oxygen species) around the world. The present study investigates the antidiabetic, anti-inflammatory, and antioxidant effects of the polyphenol fraction of Coriandrum sativum seeds (PCS). Diabetic mice were orally administered with PCS (25 and 50 mg/kg b.w.) for 28 days. Oral glucose tolerance (OGTT) was also evaluated along with the anti-inflammatory effect, assessed by measuring paw edema development induced with carrageenan in Wistar rat and the antioxidant activity assessed using two tests (β-carotene discoloration and DPPH). Treatment of diabetic mice with PCS for four weeks managed their high fasting blood glucose levels, improved their overall health, also revealed an excellent antihyperlipidemic activity. The OGTT result showed a potent antihyperglycemic activity, and following the anti-inflammatory and antioxidant effects, the PCS exhibited a perfect activity. LC-MS/MS result revealed the presence of 9 polyphenols. This modest work indicates that the PCS have an important antidiabetic, antihyperglycemic, antihyperlipidemic, anti-inflammatory, and antioxidant effect that can be well established treatment of diabetes and its complications.

Artemisia absinthium L. is one of the plants which has been used in folk medicine for many diseases over many centuries. This study aims to analyze the chemical composition of the Artemisia absinthium ethyl acetate and its aqueous extracts and to evaluate their effect on the pancreatic α-amylase enzyme and the intestinal α-glucosidase enzyme. In this study, the total contents of phenolic compounds, flavonoids, and condensed tannins in ethyl acetate and the aqueous extracts of Artemisia absinthium leaves were determined by using spectrophotometric techniques, then the antioxidant capacity of these extracts was examined using three methods, namely, the DPPH (2, 2-diphenyl-1picrylhydrazyl) free radical scavenging method, the iron reduction method FRAP, and the β-carotene bleaching method. The determination of the chemical composition of the extracts was carried out using high-performance liquid chromatography—the photodiode array detector (HPLC-DAD). These extracts were also evaluated for their ability to inhibit the activity of the pancreatic α-amylase enzyme, as well as the intestinal α-glucosidase enzyme, in vitro and in vivo, thus causing the reduction of blood glucose. The results of this study showed that high polyphenol and flavonoid contents were obtained in ethyl acetate extract with values of 60.34 ± 0.43 mg GAE/g and 25.842 ± 0.241 mg QE/g, respectively, compared to the aqueous extract. The results indicated that the aqueous extract had a higher condensed tannin content (3.070 ± 0.022 mg EC/g) than the ethyl acetate extract (0.987 ± 0.078 mg EC/g). Ethyl acetate extract showed good DPPH radical scavenging and iron reduction FRAP activity, with an IC₅₀ of 0.167 ± 0.004 mg/mL and 0.923 ± 0.0283 mg/mL, respectively. The β-carotene test indicated that the aqueous and ethyl acetate extracts were able to delay the decoloration of β-carotene with an inhibition of 48.7% and 48.3%, respectively, which may mean that the extracts have antioxidant activity. HPLC analysis revealed the presence of naringenin and caffeic acid as major products in AQE and EAE, respectively. Indeed, this study showed that the aqueous and ethyl acetate extracts significantly inhibited the pancreatic α-amylase and intestinal α-glucosidase, in vitro. To confirm this result, the inhibitory effect of these plant extracts on the enzymes has been evaluated in vivo. Oral intake of the aqueous extract significantly attenuated starch- and sucrose-induced hyperglycemia in normal rats, and evidently, in STZ-diabetic rats as well. The ethyl acetate extract had no inhibitory activity against the intestinal α-glucosidase enzyme in vivo. The antioxidant and the enzyme inhibitory effects may be related to the presence of naringenin and caffeic acid or their synergistic effect with the other compounds in the extracts.

The biological activities of propolis samples are the result of many bioactive compounds present in the propolis. The aim of the present study was to determine the various chemical compounds of some selected propolis samples collected from Palestine and Morocco by the High-Performance Liquid Chromatography–Photodiode Array Detection (HPLC-PDA) method, as well as the antioxidant and antibacterial activities of this bee product. The chemical analysis of propolis samples by HPLC-PDA shows the cinnamic acid content in the Palestinian sample is higher compared to that in Moroccan propolis. The results of antioxidant activity demonstrated an important free radical scavenging activity (2,2-Diphenyl-1-picrylhydrazyl (DPPH); 2,2′-azino-bis 3-ethylbenzothiazoline-6-sulphonic acid (ABTS) and reducing power assays) with EC₅₀ values ranging between 0.02 ± 0.001 and 0.14 ± 0.01 mg/mL. Additionally, all tested propolis samples possessed a moderate antibacterial activity against bacterial strains. Notably, Minimum Inhibitory Concentrations (MICs) values ranged from 0.31 to 2.50 mg/mL for Gram-negative bacterial strains and from 0.09 to 0.125 mg/mL for Gram-positive bacterial strains. The S2 sample from Morocco and the S4 sample from Palestine had the highest content of polyphenol level. Thus, the strong antioxidant and antibacterial properties were apparently due to the high total phenolic and flavone/flavonol contents in the samples. As a conclusion, the activities of propolis samples collected from both countries are similar, while the cinnamic acid in the Palestinian samples was more than that of the Moroccan samples.

The nutrient contents ofRaphanus sativusL. (white radish) leaves (RSLs) and roots are known to have promising vital effects. We comparatively investigated the leaves and roots ofR. sativusgrown in Saudi Arabia to estimate the total phenol and flavonoid contents using the standard colorimetric methods. The antioxidant activity of RSLs andR. sativusroots (RSRs) were measured by 2,2′-azino-bis-3-ethylbenzthiazoline-6-sulphonic acid (ABTS) and 1,1-diphenyl-2-picrylhydrazyl (DPPH) assays. Both extracts’ cytotoxic activity was assessed by MTT assay against several human cancer cell lines (A549, HepG2, MDA-MB-231, and MCF-7). High-performance thin-layer chromatography was used to identify and quantify the biomarker compound rutin in both extracts. The total phenolic content in RSLs (125.3 mg of gallic acid equivalent [GAE]/g) was higher than that in roots (95.8 of GAE/g), whereas the flavonoid content (44.5 mg of quercetin equivalent [QE]/g) was almost double compared in RSR extract (24.4 of QE/g). Similarly, RSLs exhibited a higher antioxidative activity than RSRs in both DPPH (IC₅₀216.8 vs 359.7 µg/mL) and ABTS (IC₅₀326.7 vs 549 µg/mL) models. RSLs also demonstrated the highest antiproliferative efficiency against all cell lines, with IC₅₀values of 217–453 µg/mL. The reversed-phase-high-performance thin-layer chromatography results showed the presence of rutin (5.2 µg/mg) only in RSLs. Our study indicates RSLs as a promising source of bioactive compounds compared with roots.