α-Glucosidase and α-amylase inhibitory activities of medicinal plants in Thai antidiabetic recipes and bioactive compounds from Vitex glabrata R. Br. stem bark

Isolation and In Vitro Biological Evaluation of Triterpenes from Salacia grandifolia Leaves

Salacia grandifolia is naturally found in the Atlantic Forest regions of Brazil. Despite the pharmacological potential of plants from the Salacia genus, phytochemical studies on this species have not been reported in literature. A new triterpene, 28-hydroxyfriedelane-3,15-dione (1), and seven known compounds (friedelan-3-one (2), friedelan-3β-ol (3), friedelane-3,15-dione (4), 15α-hydroxyfriedelan-3-one (5), 28-hydroxyfriedelan-3-one (6), 30-hydroxyfriedelan-3-one (7), and 29-hydroxyfriedelan-3-one (8)) were obtained from the hexane extract of Salacia grandifolia leaves. These isolated compounds and three extracts, hexane (EH), chloroform (EC), and ethyl acetate (EAE), were assessed for their potential biological activities, which consisted in the evaluation of antiviral activity against a murine coronavirus, mouse hepatitis virus 3 (MHV-3), antibacterial activity against the susceptible and methicillin-resistant Staphylococcus aureus (MRSA), and antileukemia activity against the THP-1 and K-562 cell lines. The extracts EH and EAE along with the triterpenes 1 and 6 exhibited moderate to high antiviral activity, with emphasis on 6, which presented an EC50 value of 2.9 ± 0.3 μM. None of the compounds presented antibacterial activity against the tested strains. The evaluated compounds 1, 4, 6 and 7 exhibited low cytotoxic activity against the tested leukemia cell lines. Taken together, this study comprises an overview for the potential of the Salacia grandifolia biological activities, including a new isolated triterpene.

Diospyros rhodocalyx Kurz induces mitochondrial-mediated apoptosis via BAX, Bcl-2, and caspase-3 pathways in LNCaP human prostate cancer cell line

Background

Prostate cancer (PCa) is one of the causes of death in men worldwide. Although treatment strategies have been developed, the recurrence of the disease and consequential side effects remain an essential concern. Diospyros rhodocalyx Kurz, a traditional Thai medicine, exhibits diverse therapeutic properties, including anti-cancer activity. However, its anti-cancer activity against prostate cancer has not been thoroughly explored. This study aims to evaluate the anti-cancer activity and underlying mechanisms of the ethyl acetate extract of D. rhodocalyx Kurz (EADR) related to apoptosis induction in the LNCaP human prostate cancer cell line.

Methods

Ethyl acetate was employed to extract the dried bark of D. rhodocalyx Kurz. The cytotoxicity of EADR on both LNCaP and WPMY-1 cells (normal human prostatic myofibroblast cell line) was evaluated using MTS assay. The effect of EADR on the cell cycle, apoptosis induction, and alteration in mitochondrial membrane potential (MMP) was assessed by the staining with propidium iodide (PI), Annexin V-FITC/PI, and JC-1 dye, respectively. Subsequent analysis was conducted using flow cytometry. The expression of cleaved caspase-3, BAX, and Bcl-2 was examined by Western blotting. The phytochemical profiling of the EADR was performed using gas chromatography-mass spectrometry (GC-MS).

Results

EADR exhibited a dose-dependent manner cytotoxic effect on LNCaP cells, with IC50 values of 15.43 and 12.35 µg/mL after 24 and 48 h, respectively. Although it also exhibited a cytotoxic effect on WPMY-1 cells, the effect was comparatively lower, with the IC50 values of 34.61 and 19.93 µg/mL after 24 and 48 h of exposure, respectively. Cell cycle analysis demonstrated that EADR did not induce cell cycle arrest in either LNCaP or WPMY-1 cells. However, it significantly increased the sub-G1 population in LNCaP cells, indicating a potential induction of apoptosis. The Annexin V-FITC/PI staining indicated that EADR significantly induced apoptosis in LNCaP cells. Subsequent investigation into the underlying mechanism of EADR-induced apoptosis revealed a reduction in MMP as evidenced by JC-1 staining. Moreover, Western blotting demonstrated that EADR treatment resulted in the upregulation of BAX, downregulation of BCL-2, and elevation of caspase-3 cleavage in LNCaP cells. Notably, the epilupeol was a prominent compound in EADR as identified by GC-MS.

Conclusion

The EADR exhibits anti-cancer activity against the LNCaP human prostate cancer cell line by inducing cytotoxicity and apoptosis. Our findings suggest that EADR promotes apoptosis by upregulating pro-apoptotic BAX, whereas downregulation of anti-apoptotic Bcl-2 results in the reduction of MMP and the activation of caspase-3. Of particular interest is the presence of epilupeol, a major compound identified in EADR, which may hold promise as a candidate for the development of therapeutic agents for prostate cancer.

Quality, Safety and Biological Studies on Campylanthus glaber Aerial Parts

In Cabo Verde, several endemic species are used in traditional medicine. However, no scientific studies have been conducted on the quality, efficacy, and safety of most of these plants. This study focused on establishing the botanical and chemical identification parameters required for a quality monograph of Campylanthus glaber Benth. aerial parts, a medicinal plant of Cabo Verde traditionally used to treat fever and muscular pain. In addition, in vitro antioxidant and antihyperglycemic activity, cytotoxicity, and genotoxicity were assessed for this medicinal plant. Optical microscopy, LC/UV-DAD-ESI/MS, and colorimetric assays were used for botanical, chemical, and biological studies, respectively. Cytotoxicity was assessed by the MTT assay with HepG2 cells, and genotoxicity by the Ames test. Microscopically, the xeromorphic leaf of C. glaber presents a thick cuticle (13.6-25.5 µm), thick-walled epidermal cells, anomocytic-type stomata, glandular trichomes (stalk length = 49.4-120.8 µm), and idioblasts containing calcium oxalate microcrystals. The chemical screening of aqueous and hydroethanolic extracts of this medicinal plant revealed the presence of organic acids, iridoids, phenylethanoids, and flavonoids as the main classes of marker compounds, with malic acid, citric acid, and verbascoside being the main marker compounds identified. Both extracts showed similar LC/UV-DAD/ESI-MS qualitative profiles and DPPH radical scavenger activity (IC50 = 130.9 ± 1.4; 134.3 ± 3.1 µg/mL). The hydroethanolic extract inhibited both α-amylase and α-glucosidase enzymes in a dose-dependent manner. Both extracts showed no cytotoxicity (up to 1000 µg/mL) by the MTT assay and no genotoxic potential with or without metabolic activation up to 5 mg /plate. The results obtained are an important contribution to the monographic quality assessment of C. glaber aerial parts and suggest that this medicinal plant may be safe and potentially used as an herbal drug raw material for pharmaceutical purposes.

Exploring plant-based alpha-glucosidase inhibitors: promising contenders for combatting type-2 diabetes

Objective: This systematic review aimed to provide comprehensive details on the α-G inhibitory potential of various bioactive compounds derived from natural sources.Methods: A comprehensive literature search was conducted using various databases and search engines, including Science Direct, Google Scholar, SciFinder, Web of Science, and PubMed until May, 2023.Results and conclusions: The enzyme alpha-glucosidase (α-G) is found in the brush border epithelium of the small intestine and consists of duplicated glycoside hydrolase (GH31) domain. It involves the conversion of disaccharides and oligosaccharides into monosaccharides by acting on alpha (1 → 4) and (1 → 6) linked glucose residue. Once absorbed, glucose enters the bloodstream and elevates postprandial glucose, which is associated with the development of type 2 Diabetes (T2D). Epidemic obesity, cardiovascular disease, and nephropathy are linked to T2D. Traditional medicinal plants with α-G inhibitory potential are commonly used to treat T2D due to the adverse effects of currently used α-G inhibitors miglitol, acarbose, and voglibose. Various bioactive compounds derived from natural sources, including lupenone, Wilforlide A, Baicalein, Betulinic acid, Ursolic acid, Oleanolic acid, Katononic acid, Carnosol, Hypericin, Astilbin, lupeol, betulonic acid, Fagomine, Lactucaxanthin, Erythritol, GP90-1B, Procyanidins, Galangin, and vomifoliol retain α-G inhibitory potential for regulating hyperglycaemia.

Evaluation of the antioxidant activity, genotoxic, and cytotoxic effects of the ethanolic leaves extract of Abutilon hirtum (Lam.) Sweet using in vitro assays

Abutilon hirtum (Lam.) Sweet belongs to the Malvaceae family and is a perennial shrub commonly known as Indian mallow, which is distributed in tropical regions and many different areas in Saudi Arabia. A. hirtum is an economically and a medicinally useful plant in different zones of the world for healing various diseases. The current research explores the in vitro antioxidant characteristics and cytotoxic and genotoxic potential effects of the ethanolic leaf extract of A. hirtum (LEAH). Mitotic index (MI), micronucleus (MN), and chromosomal aberration (CA) tests were performed in Allium cepa, and MTT assays were performed using human dermal fibroblast, adult (HDFa) and breast cancer (MCF7) cell lines. The comet assay was used to assess the genotoxic effect of LEAH. The antioxidant activity of LEAH was evaluated by DPPH and superoxide anion free radical scavenging assays. The results revealed that the cytotoxic effects of LEAH on Allium cepa were significantly changed in an inverse relationship with MI (general average for 3 times 0.275) and a direct relationship with MNs and CAs against concentration and treatment time, for highest concentration 1.351 mg/ml were 0.74 and 1.81 respectively. In addition, the MTT test revealed a dose-dependent cytotoxic impact, with the % cell viability decreasing as the concentration of LEAH increased, the lowest % cell viability (19.54) and highest inhibition (80.46) were obtained with 4.40 mg/ml of LEAH. In general, the results indicated that A. hirtum has a damaging effect at high doses; however, a cell safe effect, and a strong antioxidant and DNA protective effect at carefully calculated doses was observed. This provides credibility to justify its general therapeutic activity. Moreover, future studies should identify bioactive molecules and their molecular mechanisms responsible for potential therapies.

Pharmacological Potential of Betulin as a Multitarget Compound

Betulin is a natural triterpene, usually from birch bark, known for its potential wound-healing properties. Despite having a wide range of pharmacological targets, no studies have proposed betulin as a multitarget compound. Betulin has protective effects against cardiovascular and liver diseases, cancer, diabetes, oxidative stress, and inflammation. It reduces postprandial hyperglycemia by inhibiting α-amylase and α-glucosidase activity, combats tumor cells by inducing apoptosis and inhibiting metastatic proteins, and modulates chronic inflammation by blocking the expression of proinflammatory cytokines via modulation of the NFκB and MAPKs pathways. Given its potential to influence diverse biological networks with high target specificity, it can be hypothesized that betulin may eventually become a new lead for drug development because it can modify a variety of pharmacological targets. The summarized research revealed that the diverse beneficial effects of betulin in various diseases can be attributed, at least in part, to its multitarget anti-inflammatory activity. This review focuses on the natural sources, pharmacokinetics, pharmacological activity of betulin, and the multi-target effects of betulin on signaling pathways such as MAPK, NF-κB, and Nrf2, which are important regulators of the response to oxidative stress and inflammation in the body.

Anti-obesity, anti-hyperglycaemic, anti-antipyretic and analgesic activities of Globularia alypum extracts

OBJECTIVES

The aim of this study is to evaluate the anti-obesity, anti-hyperglycaemic, analgesic and antipyretic activities of Globularia alypum (GA).

MATERIALS AND METHODS

GA methanol and water extracts (GAME, GAWE) were administered to high-fat-high-glucose diet (HFFD) rats.

RESULTS

This study showed that GAME exhibited the highest antioxidant, anti-α-amylase and anti-lipase activities, with half inhibitory concentration (IC50) values 0.067, 1.05 and 2.97 mg/ml respectively. In HFFD rats, the administration of GAME inhibited lipase activity by 36, 37 and 30% in the intestine, pancreas and serum, respectively, reduced body weight by 17.7% and modulated lipid profile. In addition, administration of GAME to HFFD-rats decreased α-amylase activity, improved glucose level and protected liver function. Furthermore, the administration of GA extracts to rats revealed antipyretic (reduction in writhing by 64%) and analgesic (decrease of temperature by 1.11 °C) activities.

CONCLUSION

This study showed that GA extracts exhibited an anti-obesity, anti-hyperglycaemia, anti-pyretic and analgesic activities.

Potential of enhancing anti-obesogenic agriceuticals by applying sustainable fertilizers during plant cultivation

Overweight and obesity are two of the world's biggest health problems. They are associated with excessive fat accumulation resulting from an imbalance between energy consumed and energy expended. Conventional therapies for obesity commonly include synthetic drugs and surgical procedures that can lead to serious side effects. Therefore, developing effective, safe, and readily available new treatments to prevent and treat obesity is highly relevant. Many plant extracts have shown anti-obesogenic potential. These plant extracts are composed of different agriceuticals such as fibers, phenolic acids, flavonoids, anthocyanins, alkaloids, lignans, and proteins that can manage obesity by suppressing appetite, inhibiting digestive enzymes, reducing adipogenesis and lipogenesis, promoting lipolysis and thermogenesis, modulating gut microbiota and suppressing obesity-induced inflammation. These anti-obesogenic agriceuticals can be enhanced in plants during their cultivation by applying sustainable fertilization strategies, improving their capacity to fight the obesity pandemic. Biofertilization and nanofertilization are considered efficient, eco-friendly, and cost-effective strategies to enhance plant growth and development and increase the content of nutrients and bioactive compounds, representing an alternative to overproducing the anti-obesogenic agriceuticals of interest. However, further research is required to study the impact of anti-obesogenic plant species grown using these agricultural practices. This review presents the current scenario of overweight and obesity; recent research work describing different plant species with significant effects against obesity; and several reports exhibiting the potential of the biofertilization and nanofertilization practices to enhance the concentrations of bioactive molecules of anti-obesogenic plant species.

An insight into the potent medicinal plant Phyllanthus amarus Schum. and Thonn

Phyllanthus amarus Schum. and Thonn., a globally distributed herb is known for its several therapeutic potentials. P. amarus has a long history of use in the traditional system of medicine for over 2000 years owing to its wide array of secondary metabolites that confer significant medicinal attributes. Research on various aspects including ethnobotany, phytochemistry to bioactivity, or pharmacological studies has been conducted over the past several decades on this potent herb. P. amarus extracts have shown a broad range of pharmacological activities like hepatoprotective, antioxidant, antiviral, antimicrobial, antidiabetic, anti-inflammatory, anticancer, antimalarial, nephroprotective, diuretic, and several other properties. The present review compiles and covers literature and research of several groups across past decades to date and focuses on how the therapeutic significance of this plant can be further explored for future research either as herbal formulations, alternative medicine, or in the pharmaceutical industry.

Supplementary Information

The online version contains supplementary material available at 10.1007/s13237-022-00409-z.

Critical Assessment of In Vitro Screening of α-Glucosidase Inhibitors from Plants with Acarbose as a Reference Standard

Postprandial hyperglycemia is treated with the oral antidiabetic drug acarbose, an intestinal α-glucosidase inhibitor. Side effects of acarbose motivated a growing number of screening studies to identify novel α-glucosidase inhibitors derived from plant extracts and other natural sources. As "gold standard", acarbose is frequently included as the reference standard to assess the potency of these candidate α-glucosidase inhibitors, with many outperforming acarbose by several orders of magnitude. The results are subsequently used to identify suitable compounds/products with strong potential for in vivo efficacy. However, most α-glucosidase inhibitor screening studies use enzyme preparations obtained from nonmammalian sources (typically Saccharomyces cerevisiae), despite strong evidence that inhibition data obtained using nonmammalian α-glucosidase may hold limited value in terms of identifying α-glucosidase inhibitors with actual in vivo hypoglycemic potential. The aim was to critically discuss the screening of novel α-glucosidase inhibitors from plant sources, emphasizing inconsistencies and pitfalls, specifically where acarbose was included as the reference standard. An assessment of the available literature emphasized the cruciality of stating the biological source of α-glucosidase in such screening studies to allow for unambiguous and rational interpretation of the data. The review also highlights the lack of a universally adopted screening assay for novel α-glucosidase inhibitors and the commercial availability of a standardized preparation of mammalian α-glucosidase.

Comparative study of six antidiabetic polyherbal formulation for its multimodal approaches in diabetes management

Commercial antidiabetic polyherbal formulations (APH) are available with claimed hypoglycemic activities; yet they lack systematic scientific studies leading to their limited global acceptance. In the present study, six selected APH from the Indian market were evaluated for their phytochemical contents, anti-hyperglycemic, anti-hyperlipidemic, antioxidant activities and further identifying the major antidiabetic bioactive compound of "MA" by HPLC-ESI-MS/MS. Our results revealed highest TPC (136.97 ± 0.6 µg GAE/mg) and TFC (128.85 ± 0.74 µg QE/mg) in APH-DB and APH-SN, respectively. APH-MA has exhibited highest α-amylase 72.5% (IC₅₀-579.65 μg/ml), α-glucosidase 88.02% (IC₅₀-261.03 μg/ml) and moderate lipase inhibition 57.7% (IC₅₀ 159.57 μg/ml). A variable free radical scavenging activity was observed by all the tested APH. Further significant linear positive correlations were observed between TPC-Lipase (r ²-0.985****), TFC-α-amylase (r ²-0.868**) and DPPH-α-amylase inhibition (r ²-0.8098*). HPLC-ESI-MS/MS of MA showed the presence of anti-hyperglycemic compounds, Pheophorbide a and Pyropheophorbide a, as the major peaks. Among the tested extracts, MA exhibited better activities while BG, MH, SN, DB, and DT have showed comparable/mild anti-hyperglycemic, anti-hyperlipidemic and antioxidant potential. Hence the tested APH may be considered effective for DM management which can further be assessed for their other targets of inhibition.

Binding Interaction of Betulinic Acid to α-Glucosidase and Its Alleviation on Postprandial Hyperglycemia

Inhibiting the intestinal α-glucosidase can effectively control postprandial hyperglycemia for type 2 diabetes mellitus (T2DM) treatment. In the present study, we reported the binding interaction of betulinic acid (BA), a pentacyclic triterpene widely distributed in nature, on α-glucosidase and its alleviation on postprandial hyperglycemia. BA was verified to exhibit a strong inhibitory effect against α-glucosidase with an IC₅₀ value of 16.83 ± 1.16 μM. More importantly, it showed a synergistically inhibitory effect with acarbose. The underlying inhibitory mechanism was investigated by kinetics analysis, surface plasmon resonance (SPR) detection, molecular docking, molecular dynamics (MD) simulation and binding free energy calculation. BA showed a non-competitive inhibition on α-glucosidase. SPR revealed that it had a strong and fast affinity to α-glucosidase with an equilibrium dissociation constant (K_D) value of 5.529 × 10⁻⁵ M and a slow dissociation. Molecular docking and MD simulation revealed that BA bound to the active site of α-glucosidase mainly due to the van der Waals force and hydrogen bond, and then changed the micro-environment and secondary structure of α-glucosidase. Free energy decomposition indicated amino acid residues such as PHE155, PHE175, HIE277, PHE298, GLU302, TRY311 and ASP347 of α-glucosidase at the binding pocket had strong interactions with BA, while LYS153, ARG210, ARG310, ARG354 and ARG437 showed a negative contribution to binding affinity between BA and α-glucosidase. Significantly, oral administration of BA alleviated the postprandial blood glucose fluctuations in mice. This work may provide new insights into the utilization of BA as a functional food and natural medicine for the control of postprandial hyperglycemia.

Towards the Pharmacological Validation and Phytochemical Profiling of the Decoction and Maceration of Bruguiera gymnorhiza (L.) Lam.—A Traditionally Used Medicinal Halophyte

Decoctions (leaves and roots) of Bruguiera gymnorhiza (L.) Lam. are traditionally used against diabetes in many countries, including Mauritius. This study endeavoured to evaluate the inhibitory potential of leaves, roots, twigs and fruits extracts (decoction and maceration) of B. gymnorhiza against key enzymes relevant to diabetes. Considering complications related to diabetes, other clinical enzymes, namely, acetylcholinesterase (AChE), butyrylcholinesterase (BChE), tyrosinase, elastase and pancreatic lipase, were used. Identification of compounds was carried out using ultra-high-performance liquid chromatography/electrospray ionization tandem mass spectrometry (UHPLC-ESI-MS/MS). Antioxidant capacities were assessed using DPPH, ABTS, FRAP, CUPRAC, phosphomolybdenum, metal chelating. The relationship between mode of extraction, plant parts and biological activities was determined using multivariate analysis. Macerated fruits, rich in phytochemicals (phenolic, flavanol, tannin, and triterpenoid), exhibited substantially high antioxidant capacities related to radical scavenging (DPPH: 547.75 ± 10.99 and ABTS: 439.59 ± 19.13 mg TE/g, respectively) and reducing potential (CUPRAC: 956.04 ± 11.90 and FRAP: 577.26 ± 4.55 mg TE/g, respectively). Additionally, the same extract significantly depressed AChE and BChE (3.75 ± 0.03 and 2.19 ± 0.13 mg GALAE/g, respectively), tyrosinase (147.01 ± 0.78 mg KAE/g), elastase (3.14 ± 0.08 mg OE/g) and amylase (1.22 ± 0.01 mmol ACAE/g) enzymatic activities. Phytochemical results confirmed the presence of 119 compounds in all maceration and 163 compounds in all decoction samples. The screening also revealed important compounds in the extracts, namely, quinic acid, brugierol, bruguierol A, epigallocatechin, chlorogenic acid, to name a few. Multivariate analysis reported that the plant parts of B. gymnorhiza greatly influenced the observed biological activities in contrast to the types of extraction methods employed. Docking calculations have supported the findings of the experimental part through the high binding affinity and strong interactions of some compounds against tyrosinase, AChE, BChE and elastase enzymes. The decocted root and leaf of B. gymnorhiza showed low to moderate antidiabetic activity, thereby partially supporting its traditional uses in the management of diabetes. However, the fruit, the most active organ, can be used as a diet supplement to reduce the risk of diabetes complications after evaluating its cytotoxic effects.

A Review of Recent Studies on the Antioxidant and Anti-Infectious Properties of Senna Plants

The use of phytochemicals is gaining interest for the treatment of metabolic syndromes over the synthetic formulation of drugs. Senna is evolving as one of the important plants which have been vastly studied for its beneficial effects. Various parts of Senna species including the root, stem, leaves, and flower are found rich in numerous phytochemicals. In vitro, in vivo, and clinical experiments established that extracts from Senna plants have diverse beneficial effects by acting as a strong antioxidant and antimicrobial agent. In this review, Senna genus is comprehensively discussed in terms of its botanical characteristics, traditional use, geographic presence, and phytochemical profile. The bioactive compound richness contributes to the biological activity of Senna plant extracts. The review emphasizes on the in vivo and in vitro antioxidant and anti-infectious properties of the Senna plant. Preclinical studies confirmed the beneficial effects of the Senna plant extracts and its bioactive components in regard to the health-promoting activities. The safety, side effects, and therapeutic limitations of the Senna plant are also discussed in this review. Additional research is necessary to utilize the phenolic compounds towards its use as an alternative to pharmacological treatments and even as an ingredient in functional foods.

A Systematic Review of Orthosiphon stamineus Benth. in the Treatment of Diabetes and Its Complications

(1) Background: Orthosiphon stamineus Benth. is a traditional medicine used in the treatment of diabetes and chronic renal failure in southern China, Malaysia, and Thailand. Diabetes is a chronic metabolic disease and the number of diabetic patients in the world is increasing. This review aimed to systematically review the effects of O. stamineus in the treatment of diabetes and its complications and the pharmacodynamic material basis. (2) Methods: This systematic review was conducted following Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA), using the databases ScienceDirect, PubMed, and Web of Science. (3) Results: Thirty-one articles related to O. stamineus and diabetes were included. The mechanisms of O. stamineus in the treatment of diabetes and its complications mainly included inhibiting α-amylase and α-glucosidase activities, antioxidant and anti-inflammatory activities, regulating lipid metabolism, promoting insulin secretion, ameliorating insulin resistance, increasing glucose uptake, promoting glycolysis, inhibiting gluconeogenesis, promoting glucagon-likepeptide-1 (GLP-1) secretion and antiglycation activity. Phenolic acids, flavonoids and triterpenoids might be the main components for hypoglycemia effects in O. stamineus. (4) Conclusion: O. stamineus could be an antidiabetic agent to treat diabetes and its complications. However, it needs further study on a pharmacodynamic substance basis and the mechanisms of effective constituents.

Machine Learning and In Vitro Chemical Screening of Potential α-Amylase and α-Glucosidase Inhibitors from Thai Indigenous Plants

Diabetes mellitus is a major predisposing factor for cardiovascular disease and mortality. α-Amylase and α-glucosidase enzymes are the rate-limiting steps for carbohydrate digestion. The inhibition of these two enzymes is clinically used for the treatment of diabetes mellitus. Here, in vitro study and machine learning models were employed for the chemical screening of inhibiting the activity of 31 plant samples on α-amylase and α-glucosidase enzymes. The results showed that the ethanolic twig extract of Pinus kesiya had the highest inhibitory activity against the α-amylase enzyme. The respective ethanolic extract of Croton oblongifolius stem, Parinari anamense twig, and Polyalthia evecta leaf showed high inhibitory activity against the α-glucosidase enzyme. The classification analysis revealed that the α-glucosidase inhibitory activity of Thai indigenous plants was more predictive based on phytochemical constituents, compared with the α-amylase inhibitory activity (1.00 versus 0.97 accuracy score). The correlation loading plot revealed that flavonoids and alkaloids contributed to the α-amylase inhibitory activity, while flavonoids, tannins, and reducing sugars contributed to the α-glucosidase inhibitory activity. In conclusion, the ethanolic extracts of P. kesiya, C. oblongifolius, P. anamense, and P. evecta have the potential for further chemical characterization and the development of anti-diabetic recipes.