Antihyperglycemic Effect of Lavandula pedunculata: In Vivo, In Vitro and Ex Vivo Approaches

The Anti-Diabetic Effects of Medicinal Plants Belonging to the Liliaceae Family: Potential Alpha Glucosidase Inhibitors

Background

Diabetes mellitus is a complex metabolic disorder that has an enormous impact on people's quality of life and health. Although there is no doubt about the effectiveness of oral hypoglycemic agents combined with lifestyle management in controlling diabetes, no individual has ever been reported to have been completely cured of the disease. Globally, many medicinal plants have been used for the management of diabetes in various traditional systems of medicine. A deep look in the literature has revealed that the Liliaceae family have been poorly investigated for their antidiabetic activity and phytochemical studies. In this review, we summarize medicinal plants of Liliaceae utilized in the management of type II diabetes mellitus (T2DM) by inhibition of α-glucosidase enzyme and phytochemical content.

Methods

The literature search was conducted using databases including PubMed, ScienceDirect, and Google Scholar to find the significant published articles about Liliaceae plants utilized in the prevention and treatment of antidiabetics. Data were filtered to the publication period from 2013 to 2023, free full text and only English articles were included. The keywords were Liliaceae OR Alliaceae OR Amaryllidaceae AND Antidiabetic OR α-glucosidase.

Results

Six medicinal plants such as Allium ascalonicum, Allium cepa, Allium sativum, Aloe ferox, Anemarrhena asphodeloides, and Eremurus himalaicus are summarized. Phytochemical and α-glucosidase enzymes inhibition by in vitro, in vivo, and human studies are reported.

Conclusion

Plants of Liliaceae are potential as medicine herbs to regulating PPHG and prevent the progression of T2DM and its complication. In silico study, clinical application, and toxicity evaluation are needed to be investigated in the future.

Ifanosine: Olea europaea L. and Hyphaene thebaica L. combination, from traditional utilization to rational formulation: Preclinical and clinical efficacy on hypertensives patients

ETHNOPHARMACOLOGICAL RELEVANCE

Olea europaea L. and Hyphaene thebaica L. are commonly employed by traditional healers in Africa for treating and preventing hypertension, either individually or in a polyherbal preparation (Ifanosine).

AIM OF THE STUDY

The primary aim was to assess the antihypertensive effects of Olea europaea L. leaves aqueous extract (OEL), Hyphaene thebaica L. mesocarp extract (HT), and the Ifanosine on isolated rat aorta rings. The secondary objective was to evaluate the clinical benefits of a new oral formulation of Ifanosine.

MATERIALS AND METHODS

In vitro studies using an isometric transducer examined the antihypertensive effects of HT, OEL, and Ifanosine on rat aorta. Ussing chambers technic were employed to measure mucosal to serosal fluxes and total transepithelial electrical conductance (Gt) to assess the intestinal bioavailability of HT, OEL, and Ifanosine. HPLC was utilized to determine the phytochemical composition of OEL and HT extracts. Subchronic toxicity investigations involved two groups of rats, treated with either water (control) or Ifanosine at 5 g/kg for 28 days. Clinical benefits of the new Ifanosine formulation were evaluated in an observational study with 32 hypertensive patients receiving a fixed oral dose of 3.5 mg three times a day for 30 days.

RESULTS

Aqueous extracts induced dose-dependent relaxation of rat aorta rings, with HT and OEL having higher IC50 values than Ifanosine (IC50 = 44.76 ± 1.35 ng/mL, 58.67 ± 1.02 ng/mL, and 29.46 ± 0.26 ng/mL, respectively). The pA2 values of OEL and HT were 1 and 0.6, respectively, while Ifanosine was 0.06. Intestinal bioavailability studies revealed better Prazosin bioavailability than plant extracts. Toxicological studies demonstrated the safety of Ifanosine, supported by histological examinations and biochemical parameters in rat blood. Biochemical analyses indicated flavonoids and phenolic acids as dominant active constituents. Clinical benefits in humans included reduced SBP, DBP, LDL-c, VLDL-c, and TAG, and increased HDL-c without overt adverse effects.

CONCLUSION

This study validates the traditional use of OEL and HT for hypertension and advocates for alternative and combinatorial polyphytotherapy (ACP) to enhance traditional remedies.

Overview of Ethnobotanical-Pharmacological Studies Carried Out on Medicinal Plants from the Serra da Estrela Natural Park: Focus on Their Antidiabetic Potential

The Serra da Estrela Natural Park (NPSE) in Portugal stands out as a well-preserved region abundant in medicinal plants, particularly known for their pharmaceutical applications in diabetes prevention and treatment. This comprehensive review explores these plants' botanical diversity, traditional uses, pharmacological applications, and chemical composition. The NPSE boast a rich diversity with 138 medicinal plants across 55 families identified as traditionally and pharmacologically used against diabetes globally. Notably, the Asteraceae and Lamiaceae families are prevalent in antidiabetic applications. In vitro studies have revealed their significant inhibition of carbohydrate-metabolizing enzymes, and certain plant co-products regulate genes involved in carbohydrate metabolism and insulin secretion. In vivo trials have demonstrated antidiabetic effects, including glycaemia regulation, insulin secretion, antioxidant activity, and lipid profile modulation. Medicinal plants in NPSE exhibit various activities beyond antidiabetic, such as antioxidant, anti-inflammatory, antibacterial, anti-cancer, and more. Chemical analyses have identified over fifty compounds like phenolic acids, flavonoids, terpenoids, and polysaccharides responsible for their efficacy against diabetes. These findings underscore the potential of NPSE medicinal plants as antidiabetic candidates, urging further research to develop effective plant-based antidiabetic drugs, beverages, and supplements.

Lavandula pedunculata Polyphenol-Rich Extracts Obtained by Conventional, MAE and UAE Methods: Exploring the Bioactive Potential and Safety for Use a Medicine Plant as Food and Nutraceutical Ingredient

Nowadays, plant-based bioactive compounds (BCs) are a key focus of research, supporting sustainable food production and favored by consumers for their perceived safety and health advantages over synthetic options. Lavandula pedunculata (LP) is a Portuguese, native species relevant to the bioeconomy that can be useful as a source of natural BCs, mainly phenolic compounds. This study compared LP polyphenol-rich extracts from conventional maceration extraction (CE), microwave and ultrasound-assisted extraction (MAE and UAE). As a result, rosmarinic acid (58.68-48.27 mg/g DE) and salvianolic acid B (43.19-40.09 mg/g DE) were the most representative phenolic compounds in the LP extracts. The three methods exhibited high antioxidant activity, highlighting the ORAC (1306.0 to 1765.5 mg Trolox equivalents (TE)/g DE) results. In addition, the extracts obtained with MAE and CE showed outstanding growth inhibition for B. cereus, S. aureus, E. coli, S. enterica and P. aeruginosa (>50%, at 10 mg/mL). The MAE extract showed the lowest IC50 (0.98 mg DE/mL) for angiotensin-converting enzyme inhibition and the best results for α-glucosidase and tyrosinase inhibition (at 5 mg/mL, the inhibition was 87 and 73%, respectively). The LP polyphenol-rich extracts were also safe on caco-2 intestinal cells, and no mutagenicity was detected. The UAE had lower efficiency in obtaining LP polyphenol-rich extracts. MAE equaled CE's efficiency, saving time and energy. LP shows potential as a sustainable raw material, allowing diverse extraction methods to safely develop health-promoting food and nutraceutical ingredients.

Quality control, phytochemical profile, and biological activities of Crataegus monogyna Jacq. and Crataegus laciniata Ucria fruits aqueous extracts

The current study aimed to evaluate the phytochemical composition, quality control, and antioxidant, antibacterial, antifungal, antihyperglycemic activities, and toxicity assessment of Crataegus monogyna Jacq (C. monogyna) and Crataegus laciniata Ucria (C. laciniata) fruits aqueous extracts. The quality control of the plant material revealed that it is free of heavy metals and the acidity and ash parameters comply with international standards. HPLC-DAD analysis revealed the presence of eight phenolic compounds in the C. monogyna extract and nine compounds in the C. laciniata extract, with coumaric acid present only in the C. laciniata extract. According to the findings, both extracts are high in total polyphenols, total flavonoids, and condensed tannins. The results of the antioxidant activity revealed that our extracts have significant effects against 2, 2-diphényl 1-picrylhydrazyle (DPPH), and Ferric Reducing Antioxidant Power (FRAP). The antibacterial test revealed that the two extracts tested were effective against four bacterial strains, including Staphylococcus aureus, Escherichia coli, Enterobacter cloacae, and Shigella dysenteria, but were ineffective against Salmonella typhi, and Acinetobacter baumanii. In addition, extracts from both plants showed remarkable antihyperglycemic activity with no acute toxicity. In conclusion, the extracts studied could be a good source of bioactive molecules with antioxidant, antimicrobial, and anti-diabetic activity for pharmaceutical applications.

Phytochemical analysis and evaluation of antimicrobial, antioxidant, and antidiabetic activities of essential oils from Moroccan medicinal plants: Mentha suaveolens, Lavandula stoechas, and Ammi visnaga

Mentha suaveolens, Lavandula stoechas, and Ammi visnaga are widely used in Moroccan folk medicine against several pathological disorders, including diabetes and infectious diseases. This work was designed to determine the chemical profile of M. suaveolens (MSEO), L. stoechas (LSEO), and A. visnaga (AVEO) essential oils and assess their antimicrobial, antioxidant, and antidiabetic effects. The volatile components of LSEO, AVEO, and MSEO were analyzed using Gas Chromatography-Mass Spectrometry (GC-MS). The in vitro antidiabetic activity was assessed using α-amylase and α-glucosidase enzymes, while DPPH, FRAP, and β-carotene/linoleic acid methods were used to determine the antioxidant capacity. The antimicrobial activities were investigated using disc diffusion and broth-microdilution assays. GC-MS investigation revealed that the main components were fenchone (29.77 %) and camphor (24.9 %) for LSEO, and linalool (38.29 %) for AVEO, while MSEO was mainly represented by piperitenone oxide (74.55 %). The results of the antimicrobial evaluation showed that all examined essential oils (EOs) had noticeable antimicrobial activity against both bacteria and yeast, especially Micrococcus luteus and Bacillus subtilis. The MIC, MBC, and MFC values were ranged from 0.015 % to 0.5 %. The MBC/MIC and MFC/MIC ratios were less than or equal to 4.0 % (v/v), indicating their noticeable bactericidal and candidacidal efficacy. Moreover, the three EOs showed significant inhibitory effects on α-amylase and α-glucosidase (p < 0.05). It also exerted remarkable activity on FRAP, β-carotene, and DPPH radicals. These findings demonstrated that the tested plants have promising biological activities, validating their ethnomedicinal value and providing potential applications as natural drugs.

Essential Oils Composition and Biological Activity of Chamaecyparis obtusa, Chrysopogon nigritanus and Lavandula coronopifolia Grown Wild in Sudan

Generally, there are scant data about the constituents and eventually the biological activity of essential oils (EOs) from aromatic plants that grow naturally in Sudan. The present study aimed to determine the chemical composition, and antioxidant and enzyme inhibitory activities of EO extracted from the fruit of Chamaecyparis obtusa (Siebold and Zucc.) Endl. (family Cupressaceae), root of Chrysopogon nigritanus (Benth.) Veldkampis (family Poaceae) and aerial part of Lavandula coronopifolia Poir (family Lamiaceae). The fruit of C. obtusa contained only monoterpenes, mainly hydrogenated ones, with α-pinene (69.07%) as the major component. Oxygenated sesquiterpenes comprised the highest content of the C. nigritanus root EO with cedr-8-en-15-ol (28.69%) as the major constituent while aerial parts of L. coronopifolia contained both monoterpenes and sesquiterpenes and the oxygenated monoterpene lavandulol (26.56%) as dominant compounds. The EO of the root of C. nigritanus significantly displayed (p < 0.05) the highest anti-DPPH radical, Fe³⁺- and Cu²⁺-reducing and metal-chelating activities, while that of C. obtusa fruit significantly exerted (p < 0.05) the best anti-ABTS radical and total antioxidant activity. The two EOs significantly exhibited (p < 0.05) the highest anti-acetylcholinesterase and -butyrylcholinesterase activities, respectively, while EO of L. coronopifolia was the only oil to show a considerable inhibitory effect against the tyrosinase and α-glucosidase enzymes. In conclusion, EOs from these three plants could be natural agents with promising functional properties for food, cosmetics, and pharmaceutical applications.

Determination of Volatile Compounds of Mentha piperita and Lavandula multifida and Investigation of Their Antibacterial, Antioxidant, and Antidiabetic Properties

Mentha piperita and Lavandula multifida are widely used in Moroccan traditional medicine for the treatment of diabetes and infectious diseases. The aims of this work were the determination of the chemical composition of Mentha piperita (MPEO) and Lavandula multifida (LMEO) essential oils and the evaluation of their antibacterial, antioxidant, and antidiabetic activities. The chemical composition was determined by GC-MS analysis. The antibacterial effects were evaluated against several bacterial strains using disc diffusion, MIC, and MBC methods. The antioxidant activity was evaluated in vitro using DPPH, H₂O₂, and xanthine oxidase, and the antidiabetic activity was estimated by the inhibitory effects of α-amylase, α-glucosidase, and lipase activities. GC-MS results showed that the main compounds of MPEO were menthone (29.24%), levomenthol (38.73%), and eucalyptol (6.75%). However, eucalyptol (28.11%), 2-bornanone (11.57%), endo-borneol (7.82%), and linalyl acetate (5.22%) are the major compounds of LMEO. The results exhibited important inhibitory effects against some bacterial strains with MIC = MBC = 0.39 mg/mL for MPEO against Staphylococcus aureus ATCC. However, LMEO exhibited remarkable antioxidant and antidiabetic activities compared to MPEO. Indeed, LMEO inhibited DPPH, H₂O₂, and xanthine oxidase with concentrations of 15.23, 21.52, and 8.89 µg/mL, respectively. Moreover, LMEO exhibited α-amylase and α-glucosidase at IC₅₀ = 85.34 and IC₅₀ = 59.36 µg/mL, respectively. The findings showed that both MPEO and LMEO exhibit promising biological properties. However, the application of these species or their main bioactive compounds requires further investigation.

Lavandula pedunculata (Mill.) Cav. Aqueous Extract Antibacterial Activity Improved by the Addition of Salvia rosmarinus Spenn., Salvia lavandulifolia Vahl and Origanum compactum Benth

Lavender aqueous extracts are widely used in the Moroccan traditional medicine for their antibacterial properties. However, previous research have generally focused on investigating the antibacterial activity of lavender essential oils. The aim of this study is to evaluate the antibacterial activity of the Moroccan Lavandula pedunculata (Mill.) Cav. aqueous extract, alone, as well as in combination with extracts of other plant species known for their antibacterial activity: Salvia rosmarinus Spenn., Salvia lavandulifolia Vahl. and Origanum compactum Benth. We have tested the antibacterial activity of L. pedunculata, S. rosmarinus, S. lavandulifolia and O. compactum aqueous extracts individually and in combination against 34 strains using the agar dilution method. The combination effect was evaluated using the fractional inhibitory concentration (FIC). Polyphenol and tannin contents were determined using Folin-Ciocalteu reagent, and then some phenolic compounds were identified using UHPLC-MS. All the extracts displayed a large spectrum of antibacterial activity, especially against staphylococci, streptococci, Mycobacterium smegmatis and Proteus mirabilis. The minimum inhibitory concentration (MIC) values reached 0.15 ± 0.00 mg/mL for Staphylococcus warneri tested with S. lavandulifolia and 0.20 ± 0.07 mg/mL for Staphylococcus epidermidis tested with L. pedunculata or S. rosmarinus. Association of the L. pedunculata extract with S. rosmarinus, S. lavandulifolia and O. compactum showed synergistic effects (FIC ≤ 1). Moreover, the association of L. pedunculata with S. lavandulifolia was active against most of the Gram-negative strains resistant to the individual extracts. Determination of polyphenol and tannin contents showed the richness of the studied plants in these compounds. Additionally, chromatographic analysis demonstrated the high presence of rosmarinic acid in all the studied plant extracts. To our knowledge, this is the first study that shows the enhancing effect of the antibacterial activity of L. pedunculata aqueous extract combined with S. rosmarinus, S. lavandulifolia and O. compactum. These results confirm the effectiveness of the plant mixtures commonly used by traditional healers in Morocco and suggest that L. pedunculata might be used as an antibacterial agent either alone or, more efficiently, in combination with S. rosmarinus, S. lavandulifolia and O. compactum.