Antidiabetic effect of d-limonene, a monoterpene in streptozotocin-induced diabetic rats

Terpenoids as potential phytoconstituent in the treatment of diabetes: From preclinical to clinical advancement

BACKGROUND

Diabetes mellitus, a hyperglycemic condition associated with multitudinous organ dysfunction, is a hallmark of the metabolic disorder. This life-threatening condition affects millions of individuals globally, harming them financially, physically and psychologically in the course of therapy.

PURPOSES

The course therapy for illnesses has undergone ground-breaking transformations due to recent technical advances and insights. Alternatively, the administration of hyperglycemia-reducing agents results in several complications, including severe cardiovascular disease, kidney failure, hepatic problems, and several dermatological conditions. Consideration of alternate diabetic therapy having minimal side effects or no adverse reactions has been driven by such problems.

STUDY DESIGN

An extensive literature study was conducted in authoritative scientific databases such as PubMed, Scopus, and Web of Science to identify the studies elucidating the bioactivities of terpenoids in diabetic conditions.

METHODS

Keywords including 'terpenoids', 'monoterpenes', 'diterpenes', 'sesquiterpenes', 'diabetes', 'diabetes mellitus', 'clinical trials', 'preclinical studies', and 'increased blood glucose' were used to identify the relevant research articles. The exclusion criteria, such as English language, duplication, open access, abstract only, and studies not involving preclinical and clinical research, were set. Based on these criteria, 937 relevant articles were selected for further evaluation.

RESULTS

Triterpenes can serve as therapeutic agents for diabetic retinopathy, peripheral neuropathy, and kidney dysfunction by inhibiting several pathways linked to hyperglycemia and its complications. Therefore, it is essential to draw special attention to these compounds' therapeutic effectiveness and provide scientific professionals with novel data.

CONCLUSION

This study addressed recent progress in research focussing on mechanisms of terpenoid, its by-products, physiological actions, and therapeutic applications, particularly in diabetic and associated disorders.

1H NMR metabolomics insights into comparative diabesity in male and female zebrafish and the antidiabetic activity of DL-limonene

Zebrafish have been utilized for many years as a model animal for pharmacological studies on diabetes and obesity. High-fat diet (HFD), streptozotocin and alloxan injection, and glucose immersion have all been used to induce diabetes and obesity in zebrafish. Currently, studies commonly used both male and female zebrafish, which may influence the outcomes since male and female zebrafish are biologically different. This study was designed to investigate the difference between the metabolites of male and female diabetic zebrafish, using limonene - a natural product which has shown several promising results in vitro and in vivo in treating diabetes and obesity-and provide new insights into how endogenous metabolites change following limonene treatment. Using HFD-fed male and female zebrafish, we were able to develop an animal model of T2D and identify several endogenous metabolites that might be used as diagnostic biomarkers for diabetes. The endogenous metabolites in males and females were different, even though both genders had high blood glucose levels and a high BMI. Treatment with limonene prevented high blood glucose levels and improved in diabesity zebrafish by limonene, through reversal of the metabolic changes caused by HFD in both genders. In addition, limonene was able to reverse the elevated expression of AKT during HFD.

Functional foods of sub-Saharan Africa and their implications in the management of type 2 diabetes: A review

Throughout the world, the prevalence of metabolic diseases in general and type 2 diabetes (T2DM) in particular is constantly growing, and sub-Saharan Africa (SSA) is not spared. The use of functional foods is a more practical option among the different approaches used in the management of T2DM owing to the fact that they are relatively less costly, safer, and more accessible. In addition to their low glycemic index just like foods currently used to manage diabetes, functional foods contain bioactive compounds such as polyphenols, dietary fibers, saponins, and peptides. They are so named because they have additional health advantages beyond their basic nutritional worth. Bioactive compounds can be found in a variety of SSA plant-based foods, such as spices, fruits, vegetables, legumes, starchy foods, prepared foods, mixed foods, and prepared dishes. The goal of this review is to highlight some of the investigations into the effectiveness of local food and their antidiabetic mechanisms that have been studied in various SSA regions. Using the literature review as a basis, the authors state that SSA foods are rich in various bioactive compounds capable of regulating blood sugar through enhanced glucose tolerance, antioxidant effects, insulin sensitivity, and inhibition or activation of some key enzymes of the glucose metabolism that are linked to the prevention and management of T2DM. Many of the cited findings are preliminary, obtained from cell and preclinical studies, and therefore other studies need to be done to demonstrate the full potential of these foods to serve as bases for dietary guidelines.

Use of Monoterpenes as Potential Therapeutics in Diabetes Mellitus: A Prospective Review

Monoterpenes are secondary metabolites of plants belonging to the terpenoid class of natural products. They are the most abundant components of essential oils that are generally considered to have various pharmacological properties. These compounds are reported to have antidiabetic effects in recent years. Due to nature's complex biosynthetic machinery, they also exhibit a reasonable degree of structural complexity/diversity for further analysis in structure-activity studies. Therefore, monoterpenes as antidiabetic agents have been investigated by recent in vitro and in vivo studies extensively reported in the scientific literature and claimed by patent documents. The purpose of this survey is to provide a comprehensive and prospective review concerning the potential applications of monoterpenes in the treatment of diabetes. The data for this research were collected through the specialized databases PubMed, Scopus, Web of Science, and ScienceDirect between the years 2014 and 2022, as well as the patent databases EPO, WIPO, and USPTO. The research used 76 articles published in the leading journals in the field. The main effect observed was the antidiabetic activity of monoterpenes. This review showed that monoterpenes can be considered promising agents for prevention and/or treatment of diabetes as well as have a marked pharmaceutical potential for the development of bioproducts for therapeutics applications.

Therapeutic Potential of Myrtenal and Its Derivatives-A Review

The investigation of monoterpenes as natural products has gained significant attention in the search for new pharmacological agents due to their ability to exhibit a wide range in biological activities, including antifungal, antibacterial, antioxidant, anticancer, antispasmodic, hypotensive, and vasodilating properties. In vitro and in vivo studies reveal their antidepressant, anxiolytic, and memory-enhancing effects in experimental dementia and Parkinson's disease. Chemical modification of natural substances by conjugation with various synthetic components is a modern method of obtaining new biologically active compounds. The discovery of new potential drugs among monoterpene derivatives is a progressive avenue within experimental pharmacology, offering a promising approach for the therapy of diverse pathological conditions. Biologically active substances such as monoterpenes, for example, borneol, camphor, geraniol, pinene, and thymol, are used to synthesize compounds with analgesic, anti-inflammatory, anticonvulsive, antidepressant, anti-Alzheimer's, antiparkinsonian, antiviral and antibacterial (antituberculosis) properties. Myrtenal is a perspective monoterpenoid with therapeutic potential in various fields of medicine. Its chemical modifications often lead to new or more pronounced biological effects. As an example, the conjugation of myrtenal with the established pharmacophore adamantane enables the augmentation of several of its pivotal properties. Myrtenal-adamantane derivatives exhibited a variety of beneficial characteristics, such as antimicrobial, antifungal, antiviral, anticancer, anxiolytic, and neuroprotective properties, which are worth examining in more detail and at length.

Effect of nano-encapsulated food flavorings on streptozotocin-induced diabetic rats

Flavors and aromas are widely used in food and pharmaceutical industries to enhance food palatability. However, it is worth noting that they may also have bioactivity. This study aims to examine the potential impact of key flavors and their nanocapsules on health and diseases, such as type 2 diabetes mellitus (T2DM). The 36 nanocapsules of key flavorings were prepared by high shear homogenization (HSH). Seventy-two male Sprague-Dawley rats received a single dosage of streptozotocin (35 mg kg-1 body weight) intraperitoneally. All of the nutritional and biochemical parameters were statistically analyzed. A virtual docking study was conducted. Linalool nanoemulsion results showed the highest encapsulation efficiency (86.76%), while isoamyl acetate nanoparticles showed the lowest (69.99%). According to GC-MS analysis, encapsulation did not affect the flavoring structure with particle size distributions ranging from 277.3 to 628.8 nm. Using TEM, nanoemulsion particles appeared spherical with a desired nanometric diameter size. In the oral glucose tolerance test, flavorings in oil and nanoforms had no discernible hypoglycemia effects in normal rats. The nutritional and biochemical parameters confirmed that both normal and nanoencapsulation forms demonstrated a potential anti-hyperglycemic effect, and enhanced the rat health compared to the raw flavorings. The studied flavorings and their nanocapsules seem to have the potential double effect of a flavor compound as a food palatability enhancer with a potential beneficial effect on type 2 diabetes mellitus without any health drawbacks.

Chemical compositions and biological activities of Serevenia buxifolia essential oil leaves cultivated in Vietnam (Thua Thien Hue)

Serevenia buxifolia is an evergreen citrus plant and has attracted considerable attention due to its bioactive components and biological activities. In the present study, the essential oil (EO) from S. buxifolia cultivated in Vietnam was demonstrated to exhibit the in vitro antioxidant, thrombolytic, anti-hemolysis, anti-inflammatory, and antidiabetic activities. Briefly, the gas chromatography coupled to mass spectrometry analysis revealed that the leaf EO of S. buxifolia was composed of 33 components, with the main constituents being β-carypphyllene (32.5%), and elixene (9.8%). The extracted oil possessed a fairly high free radical scavenging activity against 2, 2-diphenyl-1-picrylhydrazyl (DPPH), with an IC₅₀ value of 190.7 μg/mL compared with positive control, α-tocopherol, IC₅₀ value of 42.6 μg/mL. The EO also exhibited thrombolytic activity: the percentage of inhibition was found to be 70.75% at 100 μL, in comparison with 87.2% for the positive control, streptokinase. For hemolytic activity, the percentage of inhibition of the EO was from 27.4% to 59.6% at concentrations from 10 to 100 μg/mL, respectively. The results of in vitro anti-inflammatory activity indicated that the EO of S. buxifolia leaves effectively protects the heat-induced denaturation, with an IC₅₀ value of 40.25 μg/mL. The EO also exhibited antidiabetic potential, with IC₅₀ values of 87.8 and 134.9 μg/mL against α-amylase and α-glucosidase, respectively. It is noteworthy that the potent biological activities of the obtained S. buxifolia oil increased in a dose-dependent manner. The results achieved show that the EO of S. buxifolia leaves can be a potential source for oxidative stress, inflammatory, and diabetic management.

L-limonene reduces aortic artery atherosclerosis by inhibiting oxidative stress/inflammatory responses in diabetic rats fed high-fat diet

Atherosclerosis, a leading cause of mortality worldwide, is driven by multiple risk factors such as diabetes. Oxidative stress and inflammation assist interrelated roles in diabetes-accelerated atherosclerosis. Thereby, treatment of diabetic atherosclerosis from an oxidative stress/inflammatory perspective seems to be a more effective modality to prevent and delay plaque formation and progression. This study aimed to evaluate the effects of l-limonene (LMN) on oxidative stress/inflammatory responses in the aortic artery of diabetic atherosclerosis-modeled rats. Male Wistar rats (n = 30, 250-280 g, 12 weeks old) were used to establish a diabetic atherosclerosis model (8 weeks) using high-fat diet/low-dose streptozotocin. LMN (200 mg/kg/day) was administered orally, starting on day 30^th before tissue sampling. Plasma lipid profiles, aortic histopathological changes, atherogenic index, aortic artery levels of oxidative stress markers (manganese superoxide dismutase, glutathione, and 8-isoprostane), inflammatory markers (tumor necrosis factor-alpha, interleukin (IL)-6, and IL-10), and expression of phosphorylated adenosine monophosphate-activated protein kinase (p-AMPK)/AMPK, Sirtuin 1 (SIRT1), and p-p65/p65 proteins were evaluated. The administration of LMN to diabetic rats improved lipid profiles, aortic histopathological morphology, and atherogenic index (P < 0.05 to P < 0.001). It also increased enzymatic antioxidant activities, decreased 8-isoprostane level, suppressed inflammatory response, upregulated p-AMPK and SIRT1 proteins, and downregulated p-p65 protein (P < 0.05 to P < 0.01). Inhibiting the AMPK through the administration of compound C significantly abolished or reversed the positive effects of LMN in diabetic rats (P < 0.05 to P < 0.01). LMN treatment had dual anti-oxidative and anti-inflammatory actions against atherosclerosis in the aortic artery of diabetic rats. Atheroprotection by LMN was mediated partly through modulation of AMPK/SIRT1/p65 nuclear factor kappa B signaling pathway. LMN appears to be a promising anti-atherosclerotic modality to improve the quality of life in diabetic patients.

Health-Promoting Properties and Potential Application in the Food Industry of Citrus medica L. and Citrus × clementina Hort. Ex Tan. Essential Oils and Their Main Constituents

Citrus is an important genus in the Rutaceae family, with high medicinal and economic value, and includes important crops such as lemons, orange, grapefruits, limes, etc. The Citrus species is rich sources of carbohydrates, vitamins, dietary fibre, and phytochemicals, mainly including limonoids, flavonoids, terpenes, and carotenoids. Citrus essential oils (EOs) consist of several biologically active compounds mainly belonging to the monoterpenes and sesquiterpenes classes. These compounds have demonstrated several health-promoting properties such as antimicrobial, antioxidant, anti-inflammatory, and anti-cancer properties. Citrus EOs are obtained mainly from peels, but also from leaves and flowers, and are widely used as flavouring ingredients in food, cosmetics, and pharmaceutical products. This review focused on the composition and biological properties of the EOs of Citrus medica L. and Citrus clementina Hort. Ex Tan and their main constituents, limonene, γ-terpinene, myrcene, linalool, and sabinene. The potential applications in the food industry have been also described. All the articles available in English or with an abstract in English were extracted from different databases such as PubMed, SciFinder, Google Scholar, Web of Science, Scopus, and Science Direct.

The Metabolomic Profile of the Essential Oil from Zanthoxylum caribaeum (syn. chiloperone) Growing in Guadeloupe FWI using GC × GC-TOFMS

The essential oil (EO) from the leaves of Zanthoxylum caribaeum (syn. Chiloperone) (Rutaceae) was studied previously for its acaricidal, antimicrobial, antioxidant, and insecticidal properties. In prior studies, the most abundant compound class found in leaf oils from Brazil, Costa Rica, and Paraguay was terpenoids. Herein, essential oil from the leaves of Zanthoxylum caribaeum (prickly yellow, bois chandelle blanc (FWI), peñas Blancas (Costa Rica), and tembetary hu (Paraguay)) growing in Guadeloupe was analyzed with comprehensive two-dimensional gas chromatography coupled to time-of-flight mass spectrometry (GC × GC-TOFMS), and thirty molecules were identified. A comparison with previously published leaf EO compositions of the same species growing in Brazil, Costa Rica, and Paraguay revealed a number of molecules in common such as β-myrcene, limonene, β-caryophyllene, α-humulene, and spathulenol. Some molecules identified in Zanthoxylum caribaeum from Guadeloupe showed some antimetabolic effects on enzymes; the in-depth study of this plant and its essential oil with regard to metabolic diseases merits further exploration.

Sesquiterpenes and monoterpenes from different varieties of guava leaf essential oils and their antioxidant potential

Despite that Sri Lanka is a biodiversity hotspot with numerous guava varieties (Psidium guajava L.), no adequate scientific research has been reported on leaf essential oil (EO) composition based on varieties and its pharmacological properties, namely antioxidant properties. Therefore, this study focused to evaluate the chemical compositions and antioxidative capacity of EOs isolated from leaves of seven guava varieties grown in Sri Lanka, including apple-guava (P. pomiferum , PGA), common-guava (P. guaja v a , PGCG), two wild-guava; cultivar of P. guajava (PGG) and a cultivar of P. guineense (PGE), two introduced varieties of P. guajava (PGK and PGP), and one introduced variety of P. guineense (PGC). The EOs were isolated using hydro-distillation and the chemical compositions were analyzed using Gas Chromatography-Mass Spectrometry (GC-MS) technique, and the compounds that showed greater than 90% matching value were considered for characterization. The yields of EOs ranged from 0.02-0.26% (w/w) where PGE produced the greatest amount. About sixty-eight chemical compounds were identified from seven varieties and Sesquiterpenes were found to be the most abundant in the PGCG, PGG, PGE, and PGA varieties, whereas monoterpenes were found to be the most abundant in PGK, PGP, and PGC varieties. The sesquiterpenes, Nerolidol (70.0-7.9%), (-)-Globulol (21.0-7.0%), and Caryophyllene (20.4-1.4%) and monoterpenes, D-Limonene (30.3-14.1 %) were found as the major compounds of all studied guava varieties. Twenty-eight compounds were identified for the first time in guava EOs, including Cadinadiene-1,4, Benzylacetaldehyde, and Epiglobulol. The antioxidant efficacy of EOs varied from 329.56 ± 2.01 to 85.70 ± 2.01 μL Trolox Eq/L, where PGE showed the highest antioxidative potential. Ultimately, the chemical constituents and antioxidant capacity of isolated EOs varied with the variety, with EO from PGE leaves exerting an amazing antioxidant capacity compared to the others and being rich in Nerolidol. The findings of this study fill the gap in the literature on chemical constituents in the EO of guava leaves, and also it will open the avenue to discover novel potential compounds with outstanding pharmacological activities from guava leaves.

Tiger nut (Cyperus esculentus L.) and date palm (Phoenix dactylifera L.) fruit blend mitigates hyperglycemia, insulin resistance and oxidative complications in type-2 diabetes models

Tiger nut and date fruit are chewy with sweet taste and are popularly consumed as food either alone, mixed or paired with other fruits, seeds and vegetables. They are locally used to treat diabetes and were separately reported to attenuate hyperglycemia in various animal models of diabetes. However, effect of tiger nut and date fruit mixture on key diabetes related parameters has not yet been reported. Therefore, we investigated the antidiabetic and antioxidant effects of the tiger nut and date blend (TDB) using in vitro and in vivo models. The TDB was prepared in equal ratio (1:1). For the in vivo study, mixture was included in the diet at 5% and 10% and feed the type 2 diabetic rats for 4 weeks. The diabetic untreated rats showed significant (p < .05) hyperglycemia, hyperlipidemia, insulin resistance and oxidative stress. Consumption of the TDB blend, significantly (p < .05) reduced fasting blood glucose by 71% and 52% in the groups treated with high and low doses respectively. In addition, intake of TBD blend demonstrated significant (p < .05) antihyperlipidemic, ameliorated insulin resistance and oxidative stress in the treated groups. The effects were more prominent in group supplemented with the 10% of the TDB and attributed to some promising ingredients detected. In conclusion, dietary supplementation of TDB exhibited antidiabetic action and could be due to the phytochemicals assessed. PRACTICAL APPLICATIONS: Inclusion of functional foods such as tiger nut and date fruit in daily diet is proved to be highly beneficial in controlling type-2 diabetes and its associated complications. Our results show that tiger nut and date fruit blend can effectively reduce hyperglycemia and oxidative damage, improve insulin sensitivity in type-2 diabetes rat model. Hence, the data shows the potential of tiger nut and date fruit blend to promote scientific basis of the dietary application of tiger nut and date fruit blend as a functional food for the remedy of diabetes and its associated complications.

Cannabinoids and terpenes for diabetes mellitus and its complications: from mechanisms to new therapies

The number of people diagnosed with diabetes mellitus and its complications is markedly increasing worldwide, leading to a worldwide epidemic across all age groups, from children to older adults. Diabetes is associated with premature aging. In recent years, it has been found that peripheral overactivation of the endocannabinoid system (ECS), and in particular cannabinoid receptor 1 (CB1R) signaling, plays a crucial role in the progression of insulin resistance, diabetes (especially type 2), and its aging-related comorbidities such as atherosclerosis, nephropathy, neuropathy, and retinopathy. Therefore, it is suggested that peripheral blockade of CB1R may ameliorate diabetes and diabetes-related comorbidities. The use of synthetic CB1R antagonists such as rimonabant has been prohibited because of their psychiatric side effects. In contrast, phytocannabinoids such as cannabidiol (CBD) and tetrahydrocannabivarin (THCV), produced by cannabis, exhibit antagonistic activity on CB1R signaling and do not show any adverse side effects such as psychoactive effects, depression, or anxiety, thereby serving as potential candidates for the treatment of diabetes and its complications. In addition to these phytocannabinoids, cannabis also produces a substantial number of other phytocannabinoids, terpenes, and flavonoids with therapeutic potential against insulin resistance, diabetes, and its complications. In this review, the pathogenesis of diabetes, its complications, and the potential to use cannabinoids, terpenes, and flavonoids for its treatment are discussed.

D-limonene (5 (one-methyl-four-[1-methylethenyl]) cyclohexane) diminishes CCl4-induced cardiac toxicity by alleviating oxidative stress, inflammatory and cardiac markers

Background: The cardiovascular crisis is advancing rapidly throughout the world. A large number of studies have shown that plant polyphenols affect major mechanisms involved in cardiovascular events through their action on the antioxidant system, signaling, and transcription pathways. D-limonene, a monocyclic monoterpene obtained from citrus fruits, is reported to possess many pharmacological activities.Methods: The experiment was designed to determine the protective effect of D-limonene against cardiac injury induced by CCl4 in Wistar rats. Rats were treated with two doses of D-limonene against cardiac injury induced by CCl4. Serum toxicity markers, cardiac toxicity biomarker enzymes, inflammatory mediators, anti-oxidant armory, lipid peroxidation, lipid profile, and histology were done.Results: CCl4 intoxication resulted in a substantial rise in FFA, TC, TG, PL, LDL, VLDL, and a reduction in HDL, restoring these changes with the administration of D-limonene at a dosage of 200 mg/kg. CCl4 administration also resulted in lipid oxidation and decreased antioxidant activity. At the same time, D-limonene at a dosage of 200 mg/kg body weight inhibited LPO and restored in vivo antioxidant components to normal. CCl4 intoxication also resulted in a significant increase in inflammatory markers like IL-6, TNF-α, high sensitivity Corticotropin Releasing Factor (Hs-CRF), and biomarkers of cardiac toxicity like alanine aminotransferase (ALT), lactate dehydrogenase (LDH), creatine kinase (CK), creatine kinase MB (CKMB), and Troponin I & troponin-t activities. D-limonene reversed all these changes to normal. Histology further confirmed our obtained results.Conclusion: These findings indicate that D-limonene can ameliorate cardiac injury at a 200 mg/kg body weight dosage. Henceforth, D-Limonene intervenes in mediating CCl4 induced toxicity by various signaling pathways.

Rosiridin Attenuates Scopolamine-Induced Cognitive Impairments in Rats via Inhibition of Oxidative and Nitrative Stress Leaded Caspase-3/9 and TNF-α Signaling Pathways

AIM

A monoterpene and bioactive component of the plant Rhodiola rosea (R. rosea), rosiridin has beneficial effects on the human central nervous system and enhances brain function. The goal of this scientific study was to determine if rosiridin might shield rats from neurocognitive problems induced by scopolamine.

METHODS

To track the potential toxicities in rats, the acute toxicity in rats was clarified. Rosiridin at a dose of 10 mg/kg was tested in rats for 14 days. At the conclusion of the investigation, behavioral parameters that were used to identify the rats' cognitive and motor abilities were evaluated. Several biochemical parameters were estimated using the prepared homogenate, including acetylcholine esterase (AChE), choline acetyltransferase (ChAT), radical scavengers produced by the body (Catalase-CAT, superoxide dismutase-SOD, and reduced glutathione-GSH), indicators of oxidative and nitrative burnout, pro-inflammatory (Interleukins- IL-1β, IL-6, interferon gamma IFN-ꝩ, and tumor necrosis factor-TNF-α), and cell apoptosis caspases 3 and 9.

RESULTS AND CONCLUSION

A significant behavioral parameter restoration was seen in the rosiridin-treated group, including reduction in latency time during acquisition and retention trial in the Morris water maze test, and percentage of spontaneous alterations in the y-maze test, when compared to the disease control group that received scopolamine; rosiridin also altered the oxidative stress and neuroinflammatory markers, as well as restoring Ach and ChAT activities and normalizing GSH, SOD, MDA, TNF-α, nitrate, IL-1β, IL-6, IFN-ꝩ, caspases 3 and 9 levels. The results imply that rosiridin limits the effect of scopolamine on rat cognitive function.

Phytochemistry and Biological Properties of Salvia verbenaca L.: A Comprehensive Review

The family Lamiaceae contains several plants used in traditional medicine to fight against different diseases. Salvia verbenaca L. (S. verbenaca) is one of the Lamiaceae species distributed around the Mediterranean regions. This plant exhibits different bioactive properties, including antibacterial, anticancer, antioxidant, antileishmanial, antidiabetic, immunomodulatory, and wound healing. This review was conducted to revise previous studies on S. verbenaca addressing its botanical description, geographical distribution, and phytochemical, pharmacological, and toxicological properties. Moreover, the main pharmacological actions of S. verbenaca major compounds were well investigated. Literature reports have revealed that S. verbenaca possesses a pivotal role in medicinal applications. The findings of this work noted that S. verbenaca was found to be rich in chemical compound classes such as terpenoids, phenolics, fatty acids, sterols, and flavonoids. Numerous studies have found that S. verbenaca essential oils and extracts have a wide range of biological effects. These results support the potential pharmacological properties of S. verbenaca and its traditional uses. This analysis can constitute a scientific basis for further refined studies on its pure secondary metabolites. Therefore, the outcome of the present work may support the perspective of identifying new therapeutical applications with detailed pharmacological mechanisms of S. verbenaca to prevent the development of some diseases such as neurodegenerative disorders. However, toxicological investigations into S. verbenaca are needed to assess any potential toxicity before it can be further used in clinical studies.

Reuse of Food Waste: The Chemical Composition and Health Properties of Pomelo (Citrus maxima) Cultivar Essential Oils

The aim of the present study is to investigate the chemical profile, antioxidant activity, carbohydrate-hydrolysing enzyme inhibition, and hypolipidemic effect of essential oils (EOs) extracted from Sicilian Citrus maxima (pomelo) flavedo. Using gas-chromatography-mass spectrometry analysis (GC-MS) we analysed the Eos of five cultivars of C. maxima, namely, ‘Chadock’, ‘Maxima’, ‘Pyriformis’, ‘Terracciani’, and ‘Todarii’, and their blends. The antioxidant activity was performed by using a multi-target approach using 2,2′-Azino-Bis-3-Ethylbenzothiazoline-6-Sulfonic acid (ABTS), 2,2-Diphenyl-1-picrylhydrazyl (DPPH), ferric reducing ability power (FRAP), and β-carotene bleaching tests. The α-amylase, α-glucosidase, and lipase-inhibitory activities were also assessed. GC-MS analyses revealed D-limonene as the main monoterpene hydrocarbon in all cultivars, albeit with different percentages in the range of 21.72–71.13%. A good content of oxygenated monoterpenes was detected for all cultivars, especially for ‘Todarii’. The analysis of the principal components (PCA), and related clusters (HCA), was performed to find chemo-diversity among the analysed samples. EOs from ‘Chadock’ and ‘Maxima’ were statistically similar to each other, and they differed from P3 in the smaller amount of sesquiterpene hydrocarbons, while the oils from ‘Terracciani’ and ‘Todarii’ were found to be chemically and statistically different. ‘Chadock’ EO was the most active to scavenge radicals (IC₅₀ values of 22.24 and 27.23 µg/mL in ABTS and DPPH tests, respectively). ‘Terracciani’ EO was the most active against both lipase and α-amylase, whereas the blends obtained by the combination (1:1 v/v) of C. maxima ‘Maxima’ + ‘Todarii’ were the most active against α-glucosidase. Generally, the blends did not exert a unique behaviour in potentiating or reducing the bioactivity of the pomelo EOs.

Health-beneficial aroma and taste compounds in a newly developed kombucha using a Huanglongbing-tolerant mandarin hybrid

Huanglongbing (HLB) is a destructive citrus greening disease; no commercially applicable measures exist. 'LB8-9' Sugar Belle^® (SB), originally developed for the fresh market, is the most HLB-tolerant cultivar among commercially available varieties. Due to the limited capacity of the fresh fruit market, there is a need to increase the demand for SB juice. Kombucha is a fermented tea beverage with black tea and sugar, and is considered a healthy drink with an increasing market. Therefore, we aim to study the potential of using SB juice in kombucha production. Regular (black tea with no citrus juice added), Hamlin (black tea with Hamlin juice added), and SB kombucha (black tea with SB juice added) were prepared and analyzed to observe the composition of aroma and taste compounds in the kombuchas. Aroma and taste compounds in the kombuchas were analyzed using gas chromatography-mass spectrometry/olfactometry and liquid chromatography-triple quadrupole mass spectrometry, respectively. For aroma compounds, SB kombucha was characterized by high concentrations of terpenes and their derivatives, which have mandarin-like aroma characteristics and health benefits such as antidiabetic and antioxidant effects. For taste compounds, SB kombucha contained higher amount of fructose and organic acids, which have the potential to increase the intensity of sweetness and sourness, and flavonoids. This would support the potential benefits of using SB to make kombucha. This study provides valuable information about the aroma and taste compounds in SB kombucha and its potential health benefits, compared with regular and Hamlin kombucha. PRACTICAL APPLICATION: This experiment provided valuable information on the elevated aroma and taste compounds, their potential health benefits, and the changes of those compounds during kombucha fermentation in 'LB8-9' Sugar Belle^® kombucha, compared to regular and Hamlin kombucha. In the absence of an effective cure or therapy for HLB, this can be the first step for developing alternative citrus product to help the citrus industry mitigate the negative impacts from HLB.

The Genus Alternanthera: Phytochemical and Ethnopharmacological Perspectives

Ethnopharmacological relevance: The genus Alternanthera (Amaranthaceae) comprises 139 species including 14 species used traditionally for the treatment of various ailments such as hypertension, pain, inflammation, diabetes, cancer, microbial and mental disorders.

Aim of the review: To search research gaps through critical assessment of pharmacological activities not performed to validate traditional claims of various species of Alternanthera. This review will aid natural product researchers in identifying Alternanthera species with therapeutic potential for future investigation.

Materials and methods: Scattered raw data on ethnopharmacological, morphological, phytochemical, pharmacological, toxicological, and clinical studies of various species of the genus Alternanthera have been compiled utilizing search engines like SciFinder, Google Scholar, PubMed, Science Direct, and Open J-Gate for 100 years up to April 2021.

Results: Few species of Alternanthera genus have been exhaustively investigated phytochemically, and about 129 chemical constituents related to different classes such as flavonoids, steroids, saponins, alkaloids, triterpenoids, glycosides, and phenolic compounds have been isolated from 9 species. Anticancer, antioxidant, antibacterial, CNS depressive, antidiabetic, analgesic, anti-inflammatory, and immunomodulator effects have been explored in the twelve species of the genus. A toxicity study has been conducted on 3 species and a clinical study on 2 species.

Conclusions: The available literature on pharmacological studies of Alternanthera species reveals that few species have been selected based on ethnobotanical surveys for scientific validation of their traditional claims. But most of these studies have been conducted on uncharacterized and non-standardized crude extracts. A roadmap of research needs to be developed for the isolation of new bioactive compounds from Alternanthera species, which can emerge out as clinically potential medicines.

Myrtenal attenuates oxidative stress and inflammation in a rat model of streptozotocin-induced diabetes

The present study was aimed to investigate the effect of myrtenal on diabetes-associated oxidative stress, lipid peroxidation (LPO), and inflammation using a rat model of streptozotocin (STZ)-induced diabetes. Following the induction of diabetes in male Wistar rats using STZ (40 mg/kg body weight), myrtenal (80 mg/kg body weight) was administered orally to diabetic rats for four weeks and then sacrificed to harvest tissues. We measured the levels of antioxidants, LPO, and proinflammatory cytokines such as tumor necrosis factor-α (TNF-α) and interleukin 6 (IL-6), and the p65 subunit of nuclear factor-kappa B (NF-kB p65). Diabetic rats revealed increased levels of LPO, proinflammatory cytokines, and NF-kB p65, and decreased levels of antioxidants in the liver and pancreas. Supplementation with myrtenal significantly attenuated the diabetes-induced changes in the liver and pancreas of diabetic rats. Our findings suggest that myrtenal may serve as an antioxidant and anti-inflammatory agent against diabetes-associated oxidative stress and inflammation.HighlightsOral administration of myrtenal improved the antioxidant status in the liver and pancreas of diabetic rats.Myrtenal treatment diminished inflammation in the liver and pancreas of diabetic rats.Myrtenal supplementation averts oxidative stress and inflammation in diabetic rats.Myrtenal could serve as a potent antioxidant and anti-inflammatory agent in the management of diabetes.

In Vitro and In Vivo Antidiabetic Potential of Monoterpenoids: An Update

Diabetes mellitus (DM) is a chronic metabolic condition characterized by persistent hyperglycemia due to insufficient insulin levels or insulin resistance. Despite the availability of several oral and injectable hypoglycemic agents, their use is associated with a wide range of side effects. Monoterpenes are compounds extracted from different plants including herbs, vegetables, and fruits and they contribute to their aroma and flavor. Based on their chemical structure, monoterpenes are classified into acyclic, monocyclic, and bicyclic monoterpenes. They have been found to exhibit numerous biological and medicinal effects such as antipruritic, antioxidant, anti-inflammatory, and analgesic activities. Therefore, monoterpenes emerged as promising molecules that can be used therapeutically to treat a vast range of diseases. Additionally, monoterpenes were found to modulate enzymes and proteins that contribute to insulin resistance and other pathological events caused by DM. In this review, we highlight the different mechanisms by which monoterpenes can be used in the pharmacological intervention of DM via the alteration of certain enzymes, proteins, and pathways involved in the pathophysiology of DM. Based on the fact that monoterpenes have multiple mechanisms of action on different targets in in vitro and in vivo studies, they can be considered as lead compounds for developing effective hypoglycemic agents. Incorporating these compounds in clinical trials is needed to investigate their actions in diabetic patients in order to confirm their ability in controlling hyperglycemia.

Neuroprotective Potential of Limonene and Limonene Containing Natural Products

Limonene is a monoterpene confined to the family of Rutaceae, showing several biological properties such as antioxidant, anti-inflammatory, anticancer, antinociceptive and gastroprotective characteristics. Recently, there is notable interest in investigating the pharmacological effects of limonene in various chronic diseases due to its mitigating effect on oxidative stress and inflammation and regulating apoptotic cell death. There are several available studies demonstrating the neuroprotective role of limonene in neurodegenerative diseases, including Alzheimer's disease, multiple sclerosis, epilepsy, anxiety, and stroke. The high abundance of limonene in nature, its safety profile, and various mechanisms of action make this monoterpene a favorable molecule to be developed as a nutraceutical for preventive purposes and as an alternative agent or adjuvant to modern therapeutic drugs in curbing the onset and progression of neurodegenerative diseases. This manuscript presents a comprehensive review of the available scientific literature discussing the pharmacological activities of limonene or plant products containing limonene which attribute to the protective and therapeutic ability in neurodegenerative disorders. This review has been compiled based on the existing published articles confined to limonene or limonene-containing natural products investigated for their neurotherapeutic or neuroprotective potential. All the articles available in English or the abstract in English were extracted from different databases that offer an access to diverse journals. These databases are PubMed, Scopus, Google Scholar, and Science Direct. Collectively, this review emphasizes the neuroprotective potential of limonene against neurodegenerative and other neuroinflammatory diseases. The available data are indicative of the nutritional use of products containing limonene and the pharmacological actions and mechanisms of limonene and may direct future preclinical and clinical studies for the development of limonene as an alternative or complementary phytomedicine. The pharmacophore can also provide a blueprint for further drug discovery using numerous drug discovery tools.

Comparison of Essential Oils of Houttuynia cordata Thunb. from Different Processing Methods and Harvest Seasons Based on GC-MS and Chemometric Analysis

Houttuyniae Herba (HH) refers to the dried aerial part of Houttuynia cordata Thunb. (DHC) or the fresh whole grass of Houttuynia cordata Thunb. (FHC), where DHC are harvested in summer and FHC around the year. However, harvest seasons and processing methods (i.e., medicinal parts and drying process) might affect the quality of HH. To compare the essential oils (EOs) of DHC and FHC and their two harvest seasons, GC-MS analysis combined with chemometric analysis was applied. The results showed that the oil yield of FHC (0.076 ± 0.030%) was higher than that of DHC (0.038 ± 0.029%), and oil yield was higher in summer than in autumn (0.044 ± 0.029% for DHC1, 0.036 ± 0.028% for DHC2, 0.084 ± 0.026% for FHC1, and 0.067 ± 0.033% for FHC2, respectively). Moreover, hierarchical cluster analysis (HCA) and principal component analysis (PCA) successfully distinguished the chemical constituents of DHC and FHC oils. Additionally, according to orthogonal partial least squares discriminant analysis (OPLS-DA), eleven components were selected as chemical markers for discriminating DHC and FHC, and two and four chemical markers for discriminating two harvest seasons of DHC and FHC, respectively. Among these markers, the average contents of α-pinene, limonene, β-phellandrene, α-terpineol, 4-tridecanone, and ethyl decanoate were higher in FHC oils. In contrast, the average contents of nonanal, 1-nonanol, β-cyclocitral, n-hexadecanoic acid, and octadecanol were higher in DHC oils. Additionally, the contents of 4-tridecanone and ethyl decanoate were both higher in DHC1 oils than in DHC2 oils. Moreover, the contents of β-myrcene and β-phellandrene were higher in FHC1 oils, while the contents of 2,6-octadien-1-ol, 3,7-dimethyl-, acetate, and (z)-phytol were higher in FHC2 oils. For these reasons, this study provides a scientific basis for quality control and clinical medication.

Activity of Selected Group of Monoterpenes in Alzheimer's Disease Symptoms in Experimental Model Studies-A Non-Systematic Review

Alzheimer's disease (AD) is the leading cause of dementia and cognitive function impairment. The multi-faced character of AD requires new drug solutions based on substances that incorporate a wide range of activities. Antioxidants, AChE/BChE inhibitors, BACE1, or anti-amyloid platelet aggregation substances are most desirable because they improve cognition with minimal side effects. Plant secondary metabolites, used in traditional medicine and pharmacy, are promising. Among these are the monoterpenes-low-molecular compounds with anti-inflammatory, antioxidant, enzyme inhibitory, analgesic, sedative, as well as other biological properties. The presented review focuses on the pathophysiology of AD and a selected group of anti-neurodegenerative monoterpenes and monoterpenoids for which possible mechanisms of action have been explained. The main body of the article focuses on monoterpenes that have shown improved memory and learning, anxiolytic and sleep-regulating effects as determined by in vitro and in silico tests-followed by validation in in vivo models.

Phytochemistry, Toxicology, and Pharmacological Properties of Origanum elongatum

Origanum elongatum L. is an endemic aromatic and medicinal plant. This work reports previous studies on O. elongatum concerning its taxonomy, botanical description, geographical distribution, bioactive compounds, toxicology, and biological effects. Chemical analyses showed that O. elongatum contains different chemical compounds, in particular volatile compounds. Pharmacological investigations showed that volatile compounds and extracts from O. elongatum exhibit different pharmacological properties, such as antibacterial, antifungal, antiviral, antioxidant, vasodilator, corrosion inhibitor, and hepatoprotective effects. Moreover, toxicological reports revealed the safety of this species. The pharmacological effects of O. elongatum could be correlated with the main compounds, which exhibit different pharmacological properties with numerous mechanism insights.

Ethnopharmacological perspectives of glucokinase activators in the treatment of diabetes mellitus

Traditional medicinal plants have wide-reaching utilisation in the treatment of diabetes especially in developing countries where medical resources are meagre. Traditionally used anti-diabetic plants act by numerous mechanisms, however, only a few of them act through activation of the glucokinase enzyme. Glucokinase is a key regulatory enzyme in glucose metabolism thereby controls glucose homeostasis and insulin secretion. The present review significantly analyses the knowledge about various plant-based glucokinase activators including numerous phytochemicals which modulate the activity and gene expression of glucokinase and would provide data support and perspective regarding future research in the discovery and development of different plant-derived glucokinase activators.

Isoprenoid Derivatives of Lysophosphatidylcholines Enhance Insulin and GLP-1 Secretion through Lipid-Binding GPCRs

Insulin plays a significant role in carbohydrate homeostasis as the blood glucose lowering hormone. Glucose-induced insulin secretion (GSIS) is augmented by glucagon-like peptide (GLP-1), a gastrointestinal peptide released in response to ingesting nutriments. The secretion of insulin and GLP-1 is mediated by the binding of nutrients to G protein-coupled receptors (GPCRs) expressed by pancreatic β-cells and enteroendocrine cells, respectively. Therefore, insulin secretagogues and incretin mimetics currently serve as antidiabetic treatments. This study demonstrates the potency of synthetic isoprenoid derivatives of lysophosphatidylcholines (LPCs) to stimulate GSIS and GLP-1 release. Murine insulinoma cell line (MIN6) and enteroendocrinal L cells (GLUTag) were incubated with LPCs bearing geranic acid (1-GA-LPC), citronellic acid (1-CA-LPC), 3,7-dimethyl-3-vinyloct-6-enoic acid (GERA-LPC), and (E)-3,7,11-trimethyl- 3-vinyldodeca-6,10-dienoic acid (1-FARA-LPC). Respective free terpene acids were also tested for comparison. Besides their insulin- and GLP-1-secreting capabilities, we also investigated the cytotoxicity of tested compounds, the ability to intracellular calcium ion mobilization, and targeted GPCRs involved in maintaining lipid and carbohydrate homeostasis. We observed the high cytotoxicity of 1-GERA-LPC and 1-FARA-LPC in contrast 1-CA-LPC and 1-GA-LPC. Moreover, 1-CA-LPC and 1-GA-LPC demonstrated the stimulatory effect on GSIS and 1-CA-LPC augmented GLP-1 secretion. Insulin and GLP-1 release appeared to be GPR40-, GPR55-, GPR119- and GPR120-dependent.

Anti-hyperglycemic and anti-dyslipidemic activities of methanol ripe fruit extract of Duranta erecta L (Verbenaceae) in normoglycemic and hyperglycemic rats

Image 1.

Chemical Composition and Pharmacological Evaluation and of Toddalia asiatica (Rutaceae) Extracts and Essential Oil by in Vitro and in Silico Approaches

Toddalia asiatica (L.) Lam. is extensively used in traditional medicinal systems by various cultures. Despite its frequent use in traditional medicine, there is still a paucity of scientific information on T. asiatica growing on the tropical island of Mauritius. Therefore, the present study was designed to appraise the pharmacological and phytochemical profile of extracts (methanol, ethyl acetate and water) and essential oil obtained from aerial parts of T. asiatica. Biological investigation involved the evaluation of in vitro antioxidant and enzyme inhibitory potentials. The chemical profile of the EO was determined using gas chromatography coupled to mass spectrometry (GC/MS) analysis, while for the extracts, the total phenolic (TPC) and flavonoid content were quantified as well as their individual phenolic compounds by LC/MS/MS. Quinic acid, fumaric acid, chlorogenic acid, quercitrin and isoquercitrin were the main compounds in the extracts. Highest total phenolic (82.5±0.94 mg gallic acid equivalent (GAE/g)) and flavonoid (43.8±0.31 mg rutin equivalent (RE/g)) content were observed for the methanol extract. The GC/MS analysis has shown the presence of 26 compounds with linalool (30.9 %), linalyl acetate (20.9 %) and β-phellandrene (7.9 %) being most abundant components in the EO. The extracts and EO showed notable antioxidant properties, with the methanol extract proved to be superior source of antioxidant compounds. Noteworthy anti-acetylcholinesterase (AChE) and anti-butyrylcholinesterase (BChE) effects were recorded for the tested samples, while only the methanol and ethyl acetate extracts were active against tyrosinase. With respect to antidiabetic effects, the extracts and EO were potent inhibitors of α-glucosidase, while modest activity was recorded against α-amylase. Docking results showed that linalyl acetate has the highest affinity to interact with the active site of BChE with docking score of -6.25 kcal/mol. The findings amassed herein act as a stimulus for further investigations of this plant as a potential source of bioactive compounds which can be exploited as phyto-therapeutics.

Chemopreventive Potential of Myrtenal against Nitrosamine-Initiated, Radiation-Promoted Rat Bladder Carcinogenesis

The present study was undertaken to evaluate the chemopreventive activity of myrtenal, a natural monoterpene, against bladder carcinoma in rats induced with N-butyl-N-(4-hydroxybutyl)-nitrosamine (BBN) and promoted with γ-ionizing radiation (γ-IRR) as well as to assess the involvement of inflammation, apoptosis and oxidative damage in tumor development. Histopathological examination of rat bladder revealed the presence of noninvasive papillary transitional cell carcinoma (Grade 2) in sections from BBN group indicating the credibility of the applied carcinogenesis model. Myrtenal treatment caused improvement in urinary bladder mucosa with cells more likely in Grade 1. Administration of myrtenal to BBN-treated rats exhibited downregulation in the expressions of COX-2, NF-kB and STAT-3 associated with suppression of inflammatory cytokines levels of TNF-α and IL-6 as well as biomarkers of oxidative damage (MDA & NO). In addition, myrtenal treatment caused a significant increase in caspase-3 activity and Bax/Bcl-2 ratio. Data obtained suggested that the anti-inflammatory effect and the induction of apoptosis contributed largely to the beneficial antitumor effects of myrtenal in rats with BBN/γ-IRR-induced bladder carcinoma. Present findings, in addition to benefits described in other pathologies, indicated myrtenal as a potential adjuvant natural compound for the prevention of tumor progression of bladder cancer.

D-Limonene Alleviates Acute Kidney Injury Following Gentamicin Administration in Rats: Role of NF-κB Pathway, Mitochondrial Apoptosis, Oxidative Stress, and PCNA

Clinical application of gentamicin (GM) is well known to be associated with the development of acute kidney injury (AKI). This study was the first to investigate the possible protective effects of D-limonene (D-lim) on AKI following GM administration in rats. 32 rats arranged in four groups (n = 8): (1) the control group received saline intraperitoneally (0.5 ml/day) and orally (0.5 ml/day), (2) the D-lim group received D-lim (100 mg/kg) orally and saline (0.5 ml/day) intraperitoneally, (3) the GM group received GM (100 mg/kg/day) intraperitoneally and saline (0.5 ml/day) orally, and (4) the treated group received intraperitoneal GM (100 mg/kg) and oral D-lim (100 mg/kg). All treatments were performed daily for 12 consecutive days. Results revealed that D-lim ameliorated GM-induced AKI, oxidative stress, mitochondrial apoptosis, and inflammation. D-lim showed nephroprotective effects as reflected by the decrease in serum urea and creatinine and improvement of renal histopathological changes. D-lim alleviated GM-induced oxidative stress by increasing the activities of renal catalase, serum and renal glutathione peroxidase, and renal superoxide dismutase and decreasing renal malondialdehyde and serum nitric oxide levels. Intriguingly, D-lim suppressed mitochondrial apoptosis by considerably downregulating Bax and caspase-3 (Casp-3) mRNA and protein expressions and markedly enhancing Bcl2 mRNA and protein expressions. Furthermore, D-lim significantly decreases GM-induced inflammatory response through downregulation of NF-κB, IL-6, and TNF-α mRNA and/or protein expressions and decrease in renal myeloperoxidase activity. Finally, D-lim remarkably downregulated PCNA protein expression in the treated group compared with the GM group. In brief, this study showed that D-lim alleviated AKI following GM administration in rats, partially through its antioxidant, anti-inflammatory, and antiapoptotic activities as well as downregulation of PCNA expression.

Determination of Chemical Composition and α-amylase Inhibitory Effect of New Propolis Extracts

Background:

Propolis is a resinous mixture collected by honeybees from tree buds and exudates of the plants. Propolis contains aromatic acids, diterpenic acids and phenolic compounds and these components are responsible for its antitumor, anticancer, antiviral and antifungal effects. Propolis can be extracted and the solubility of propolis differs depending on the solvent used in the process of extraction. Solvents used for propolis extraction have a great impact on the propolis extract and should be nontoxic.

Objective:

In this study, raw propolis was extracted by peppermint and clove volatile oils.

Methods:

Chemical composition of extracts was determined by using GC-MS equipment. Total phenolic content and antioxidant activity of the extracts were measured. α-amylase inhibitory activity of the extracts was carried out as well.

Results:

The findings of the present study showed that clove volatile oil is more effective in the extraction of propolis than peppermint volatile oil. The total phenolic content of these extracts was determined as 175.12 and 40.80 mg GAE/mL for clove and peppermint oil propolis extracts, respectively. All extracts contained the same phenolic compounds but the quantity was less in volatile oil extract than in ethanol extract. Both of these extracts showed better α-amylase ınhibitory activity than a reference inhibitor, acarbose.

Conclusion:

It could be concluded that propolis extract obtained by using volatile oils could be used as a complementary agent in the treatment of type 2 diabetes mellitus.

D-limonene: A multifunctional compound with potent therapeutic effects

D-limonene or 4-isopropenyl-1-methylcyclohexene (C₁₀ H₁₆ ) is a monocyclic monoterpene abundant in citrus plants like lemon, orange, and grape. The application of D-limonene in the form of flavor and fragrance additive in perfumes, soaps, foods, and beverages is consistently increased due to its high-quality fragrance property. This review is intended to analyze and delineate every possible available evidence and details about D-limonene with the special focus on its therapeutic efficacy. Many studies have reported that D-limonene effectively plays a valuable role in the prevention of several chronic and degenerative diseases. This review provides worthy information about the beneficial effects of D-limonene such as antioxidant, antidiabetic, anticancer, anti-inflammatory, cardioprotective, gastroprotective, hepatoprotective, immune modulatory, anti-fibrotic, anti-genotoxic etc. This could in turn help in the application of D-limonene for clinical studies. PRACTICAL IMPLICATIONS: Various plant families contain Terpenes as their secondary metabolites. Monoterpenes constitute an important part of these secondary metabolites. D-limonene is a well-identified monoterpene that is commonly applied as a fragrance ingredient in essential oils. D-limonene is known to possess remarkable biological activities. It can be effectively used for treating various ailments and diseases. Due to its diverse functions, it can be efficiently utilized for human health.

In Silico Prediction of the Mode of Action of Viola odorata in Diabetes

Background

The metabolic syndrome increases the risk of different diseases such as type 2 diabetes. The prevalence of metabolic syndrome has rapidly grown and affected more than 230 million people worldwide. Viola odorata is a traditionally used plant for the treatment of diabetes; however, its mechanism to manage diabetes is still unknown.

Purpose

This study was designed to systematically assess the mechanism of action of Viola odorata in diabetes.

Methods

An extensive literature search was made to establish an ingredient-target database of Viola odorata. Of these, targets related to diabetes were identified and used to develop a protein-protein interaction network (PPIN) by utilizing the STITCH database. The obtained PPIN was assessed through Gene Ontology (GO) enrichment analysis based on ClueGO plugin.

Results

According to the acquired data, there were about 143 chemical constituents present in Viola odorata having 119 protein targets. Of these, 31 targets were established to give the pharmacological effect against diabetes. The UniProt database was used for screening of 31 targets, out of which Homo sapiens contained 22 targets. Ultimately, 207 GO terms, grouped into 41 clusters, were found by gene analysis, and most of them were found to be linked with diabetes. According to findings, several proteins including TP53, BCL2, CDKN1A, 1L6, CCND1, CDKN2A, and RB1 have a significant role in the treatment of diabetes by Viola odorata.

Conclusion

The possible activity of Viola odorata in the management of diabetes may be mediated by several molecular mechanisms, including the glutamine metabolic process, IRE1-mediated unfolded protein response, and pentose metabolic process.

Metabolic and clinical responses to Bunium Persicum (black caraway) supplementation in overweight and obese patients with type 2 diabetes: a double-blind, randomized placebo-controlled clinical trial

Background

Diabetes mellitus is the most common metabolic disorder worldwide. We aimed to determine the metabolic and clinical responses to Bunium Persicum (Black Caraway) supplementation in overweight and obese patients with T2DM.

Methods

Participant recruitment took place in the diabetic clinic of Bu-Ali hospital in Zahedan. Due to the eligibility criteria, 60 participants were randomly placed into two groups, namely placebo (n = 30) and BP (n = 30). The supplementation was considered one 1000 mg capsule 2 times /day BP by meals (lunch and dinner) for 8 weeks. Physical activity levels, dietary intakes, anthropometric measurements [weight, height, and waist circumference], glycemic indices [fasting blood glucose (FBG) and insulin (FBI)], blood lipids [triglyceride (TG), total cholesterol (TC), high-density lipoprotein cholesterol (HDL-c), and low-density lipoprotein cholesterol (LDL-c)], and serum nesfatin-1 level were determined. Homeostasis model assessment-insulin resistance (HOMA-IR), Quantitative insulin sensitivity checks index (QUICKI), and Body Mass Index (BMI) were computed.

Results

In comparison with placebo, BP significantly decreased FBG, HOMA-IR, and BMI (P <  0.05). The differences in the FBI, QUICKI, TG, TC, LDL, HDL, WC, and Nesfatin-1 were not significant (P > 0.05).

Conclusion

BP supplementation improved serum glucose indices and BMI among overweight and obese T2DM patients. Further trials are needed to confirm results.

Trial registration

Iranian Registry of Clinical Trials (IRCT), IRCT20181207041876N1, Registered 18/01/2019, https://irct.ir/trial/35752

Essential Oil-Bearing Plants From Balkan Peninsula: Promising Sources for New Drug Candidates for the Prevention and Treatment of Diabetes Mellitus and Dyslipidemia

Metabolic diseases like diabetes mellitus or dyslipidemia have a complex etiology characterized by the interference of genetic predisposition and environmental factors like diet or lifestyle. Over time they can cause significant vascular complications, leading to dysfunction or failure of key organs (brain, heart), with possible fatal consequences or a severe reduction of life quality. Although current authorized drugs may successfully control blood glucose or cholesterol level, their use is often associated with severe side effects, therefore the development of new drug candidates is necessary for a better management of metabolic diseases. Among potential new drug sources, aromatic plants rich in essential oils like Melissa officinalis L., Mentha x piperita L., Cuminum cyminum L. or Pistacia lentiscus L. var. chia are very promising due to their diverse chemical composition and multiple mechanisms of action. This review describes a series of recent experimental studies investigating antidiabetic and hypolipemic effects of essential oils extracted from several aromatic plant species with an ethnopharmacological relevance in the Balkan peninsula. The pharmacological models used in the studies together with the putative mechanisms of action of the main constituents are also detailed. The presented data clearly sustain a potential administration of the studied essential oils for the prevention and treatment of metabolic diseases. Further research is needed in order to ascertain the therapeutic importance of these findings.

Citrus limon (Lemon) Phenomenon-A Review of the Chemistry, Pharmacological Properties, Applications in the Modern Pharmaceutical, Food, and Cosmetics Industries, and Biotechnological Studies

This review presents important botanical, chemical and pharmacological characteristics of Citrus limon (lemon)—a species with valuable pharmaceutical, cosmetic and culinary (healthy food) properties. A short description of the genus Citrus is followed by information on the chemical composition, metabolomic studies and biological activities of the main raw materials obtained from C. limon (fruit extract, juice, essential oil). The valuable biological activity of C. limon is determined by its high content of phenolic compounds, mainly flavonoids (e.g., diosmin, hesperidin, limocitrin) and phenolic acids (e.g., ferulic, synapic, p-hydroxybenzoic acids). The essential oil is rich in bioactive monoterpenoids such as D-limonene, β-pinene, γ-terpinene. Recently scientifically proven therapeutic activities of C. limon include anti-inflammatory, antimicrobial, anticancer and antiparasitic activities. The review pays particular attention, with references to published scientific research, to the use of C. limon in the food industry and cosmetology. It also addresses the safety of use and potential phototoxicity of the raw materials. Lastly, the review emphasizes the significance of biotechnological studies on C. limon.

Identification of Odor Active Compounds in Physalis peruviana L

The volatiles of cape gooseberry fruit (Physalis peruviana L.) were isolated by solvent-assisted flavor evaporation (SAFE), odor active compounds identified by gas chromatography–olfactometry (GC-O) and gas chromatography–mass spectrometry (GC-MS). Quantitation of compounds was performed by headspace—solid phase microextraction (HS-SPME) for all but one. Aroma extract dilution analysis (AEDA) revealed 18 odor active regions, with the highest flavor dilution values (FD = 512) noted for ethyl butanoate and 4-hydroxy-2,5-dimethylfuran-3-one (furaneol). Odor activity values were determined for all 18 compounds and the highest was noted for ethyl butanoate (OAV = 504), followed by linalool, (E)-non-2-enal, (2E,6Z)-nona-2,6-dienal, hexanal, ethyl octanoate, ethyl hexanoate, butane-2,3-dione, and 2-methylpropanal. The main groups of odor active compounds in Physalis peruviana L. were esters and aldehydes. A recombinant experiment confirmed the identification and quantitative results.

Hesperidin, a citrus flavonoid ameliorates hyperglycemia by regulating key enzymes of carbohydrate metabolism in streptozotocin-induced diabetic rats

The present study investigated the protective effect of hesperidin on carbohydrate metabolizing enzymes in streptozotocin-induced diabetic rats. Hesperidin was administered to streptozotocin-induced (40 mg/kg b.w.) diabetic rats at different dosages of (25, 50, 100 mg/kg b.w.) respectively for 30 days to evaluate its effect on fasting plasma glucose, insulin, glycosylated hemoglobin, hemoglobin, and carbohydrate metabolic enzymes. The plasma glucose levels were significantly reduced in a dose-dependent manner in hesperdin-treated group of rats when compared to the diabetic control rats. In addition, concomitant increase in hemoglobin and insulin levels and a decrease in glycosylated hemoglobin were observed in treated group of rats. The activities of the hepatic key enzymes of carbohydrate metabolism such as hexokinase and glucose-6-phosphate dehydrogenase were significantly increased, whereas glucose-6-phosphatase and fructose-1,6-bisphosphatase were significantly decreased. Furthermore, hesperidin administration prevented the loss in body weight and improved the glycogen content in the hepatic tissue of diabetic animals by reinstating the activities of glycogen synthase and glycogen phosphorylase. These results showed that hesperidin has potential antihyperglycemic activity in streptozotocin-induced diabetic rats. This was further supported by the histological studies of pancreas and liver.