Hermetica Superfood Encyclopedia
The Short Answer
Combretum quadrangulare contains a diverse array of flavonoids—including ayanin, rhamnocitrin, ombuin, kumatakenin, luteolin, apigenin, and vitexin—alongside a hepatoprotective gallic acid glycoside, which collectively inhibit alpha-glucosidase (IC₅₀ 30.5–282.0 µM), HIV-1 integrase (IC₅₀ 2.5–2.9 µg/mL in root/seed extracts), and protect hepatocytes from TNF-α-induced cell death. Preclinical data show antiplasmodial activity against Plasmodium falciparum K1 with IC₅₀ values as low as 1.25 µg/mL in methanolic stem extracts, and moderate antibacterial activity against MRSA, though no human clinical trials have yet confirmed these effects in vivo.
CategoryHerb
GroupSoutheast Asian
Evidence LevelPreliminary
Primary KeywordCombretum quadrangulare benefits
Combretum quadrangulare — botanical close-up
Health Benefits
**Antiplasmodial Activity**
Ethanolic leaf, root, and stem bark extracts demonstrate inhibitory activity against chloroquine-resistant Plasmodium falciparum K1 strain, with methanolic stem extracts achieving IC₅₀ values of 1.25 µg/mL, suggesting potential utility as an adjunct antimalarial botanical pending clinical validation.
**Alpha-Glucosidase Inhibition (Antidiabetic Potential)**
Flavonoids including ayanin, rhamnocitrin, ombuin, and synthetic brominated analogues inhibit alpha-glucosidase with IC₅₀ values ranging 30.5–282.0 µM; brominated derivatives act via noncompetitive inhibition, binding allosteric sites outside the enzyme active site, which may slow postprandial glucose absorption.
**Hepatoprotection**
A purified O-galloyl-6-O-(4-hydroxy-3,5-dimethoxy)benzoyl-β-D-glucose derivative from methanolic extracts protects hepatocytes against D-galactosamine/TNF-α-induced apoptosis, and the crude methanolic extract reduced serum glutamate pyruvate transaminase (GPT) in LPS-challenged mice (extract IC₅₀ 56.4 µg/mL).
**Antiviral (HIV-1 Integrase Inhibition)**
Aqueous and ethanolic root and seed extracts inhibit HIV-1 integrase with IC₅₀ values of 2.5–2.9 µg/mL in cell-free enzymatic assays, suggesting flavonoid and polyphenolic constituents may interfere with strand-transfer steps of viral DNA integration.
**Antibacterial Activity**
Isolated flavonoids rhamnocitrin and ombuin exhibit moderate antibacterial action against methicillin-resistant Staphylococcus aureus (MRSA), with activity attributed to flavonoid-mediated disruption of bacterial membrane integrity and inhibition of bacterial target enzymes, though they were inactive against ESBL-producing Escherichia coli.
**Anthelmintic Properties**
Ether and ethanolic root and seed extracts produced in vitro killing of earthworms (Pheretima posthuma), consistent with the broad genus-level anthelmintic tradition; this activity is analogous to findings in the related species Combretum mucronatum, which showed activity in a human guinea worm trial at 0.03 mg/kg.
**Antioxidant and Anti-inflammatory Effects**
The rich flavonoid and tannin content—including myricetin derivatives, quercetin-3,4-dimethyl ether, and gallic acid conjugates—confer free radical scavenging and anti-inflammatory properties that underpin the plant's traditional use for wound healing and diarrhea management in Thai and Vietnamese ethnomedicine.
Origin & History
Natural habitat
Combretum quadrangulare Kurz is native to mainland Southeast Asia, with documented distribution across Thailand, Vietnam, Myanmar, and Cambodia, where it grows in tropical and subtropical lowland forests and disturbed secondary vegetation. The plant belongs to the Combretaceae family and thrives in humid, warm climates with seasonal rainfall typical of the Indochinese peninsula. Leaves, roots, seeds, and stem bark are all harvested from wild populations for traditional medicinal use, with no large-scale commercial cultivation currently documented.
“Combretum quadrangulare has been employed in traditional medicine across Thailand and Vietnam for centuries, with documented uses encompassing wound treatment, management of diarrheal illness, hepatic complaints, parasitic infections, and febrile conditions consistent with malaria-endemic environments. In Thai ethnobotany, the plant is used topically and internally, with leaf preparations applied to wounds and decoctions consumed for gastrointestinal disorders, reflecting the convergent discovery of its antimicrobial and anti-inflammatory properties across regional healing traditions. Vietnamese traditional practitioners similarly employ the plant for infections and liver conditions, and phytochemical investigation of Vietnamese specimens has identified a distinct but overlapping flavonoid profile compared to Thai collections, suggesting some regional chemotypic variation. Pharmacognostic interest in the genus Combretum dates to the 1970s when secondary metabolite isolation began systematically documenting the flavonoid richness of the Combretaceae family, and C. quadrangulare has been a subject of increasing phytochemical scrutiny since that period.”Traditional Medicine
Scientific Research
The evidence base for Combretum quadrangulare consists entirely of in vitro biochemical assays, phytochemical isolation studies, and a small number of rodent in vivo experiments, with zero published human clinical trials specifically on this species as of the available literature. Antiplasmodial activity has been assessed against P. falciparum K1 in multiple extract screenings (IC₅₀ 1.25–4.0 µg/mL), and the hepatoprotective gallic acid derivative was evaluated in D-galactosamine/LPS-challenged mice, though sample sizes and full statistical reporting are absent from available sources. Alpha-glucosidase inhibition data are the most mechanistically detailed, supported by enzyme kinetics experiments and in silico molecular docking for brominated flavonoid analogues, lending moderate confidence to this specific pharmacological claim within preclinical parameters. A single human trial exists within the Combretum genus (C. mucronatum in 88 adults with guinea worm infection), providing indirect contextual support for anthelmintic activity, but this cannot be extrapolated directly to C. quadrangulare without species-specific clinical study.
Preparation & Dosage
Traditional preparation
**Traditional Leaf Decoction (Thai/Vietnamese medicine)**
Dried leaves are boiled in water or extracted with 90–95% ethanol for wound-washing preparations and antidiarrheal decoctions; no standardized dose is established.
**Methanolic/Ethanolic Extract (Preclinical research)**
Root, seed, and stem bark extracted with MeOH or 90–95% EtOH; in vitro antiplasmodial activity observed at 1.25–4.0 µg/mL, with hepatoprotective extract activity at IC₅₀ 56.4 µg/mL; these are in vitro concentrations and do not translate directly to oral dosing.
**Aqueous Extract (Antiviral research)**
Water-extracted root and seed material inhibited HIV-1 integrase at IC₅₀ 2.5 µg/mL in enzymatic assay; no oral bioavailability data are available to inform human dosing.
**Ether/Dichloromethane Extract (Anthelmintic use)**
Ether and methylene chloride extracts of roots and seeds demonstrated in vitro anthelmintic activity; preparation involves cold maceration or Soxhlet extraction of dried root material.
**No Commercial Supplement Form Established**
Combretum quadrangulare is not currently available as a standardized capsule, tablet, or tincture with defined phytochemical specifications; no standardization percentages for flavonoid content have been validated for commercial use.
**Timing**
No clinical timing data exist; traditional preparations are typically administered acutely for infection or wound management rather than as chronic supplementation.
Nutritional Profile
Combretum quadrangulare is a medicinal botanical rather than a dietary food, and no conventional macronutrient or micronutrient profile has been established through proximate analysis. The dominant phytochemical constituents are polymethoxylated and hydroxylated flavonoids—including kumatakenin, ayanin, rhamnocitrin, ombuin, luteolin, apigenin, vitexin, isoorientin, mearnsetin, gardenin D, quercetin-3,4-dimethyl ether, combretol, myricetin-3,3,4-trimethyl ether, and myricetin-3,7,3',5'-tetramethyl ether—alongside hydrolyzable tannins and the gallic acid glycoside O-galloyl-6-O-(4-hydroxy-3,5-dimethoxy)benzoyl-β-D-glucose. Quantitative concentrations (mg/g dry weight) for individual phytochemicals have not been reported in available studies; yields vary significantly by plant part (leaves yield flavonoids most abundantly), extraction solvent polarity (ether vs. MeOH vs. water), and geographic provenance. Bioavailability of these flavonoids in humans is entirely unstudied for this species, though polymethoxylated flavones as a class are generally better absorbed than their polyhydroxylated counterparts due to reduced first-pass glucuronidation.
How It Works
Mechanism of Action
The primary mechanism of antidiabetic activity involves competitive and noncompetitive inhibition of intestinal alpha-glucosidase by flavonoids such as ayanin, rhamnocitrin, and ombuin, with brominated synthetic analogues (compounds 8 and 11) confirmed via enzyme kinetics and molecular docking to occupy allosteric binding sites distinct from the catalytic active site, thereby reducing the rate of oligosaccharide hydrolysis and postprandial glucose release. Hepatoprotection is mediated by the gallic acid glycoside O-galloyl-6-O-(4-hydroxy-3,5-dimethoxy)benzoyl-β-D-glucose, which suppresses TNF-α-triggered hepatocyte apoptosis through antioxidant scavenging and likely NF-κB pathway modulation, reducing oxidative stress markers including serum GPT in murine LPS models. HIV-1 integrase inhibition by root and seed extracts (aqueous IC₅₀ 2.5 µg/mL; ethanolic IC₅₀ 2.9 µg/mL) is attributed to polyphenolic constituents that chelate the Mg²⁺ cofactor in the integrase active site or sterically obstruct the strand-transfer reaction, though specific residue-level interactions have not been fully characterized. Antibacterial activity against MRSA by rhamnocitrin and ombuin likely reflects flavonoid-mediated inhibition of bacterial DNA gyrase or disruption of cytoplasmic membrane potential, consistent with class-wide mechanisms established for structurally related flavones.
Clinical Evidence
No randomized controlled trials, observational cohort studies, or other formal clinical investigations have been conducted specifically with Combretum quadrangulare in human participants, representing a significant gap in the evidence base. The only genus-level human data derive from a single trial of Combretum mucronatum (n=88) for guinea worm infection at 0.03 mg/kg orally, which reported activity but lacked detailed effect sizes and statistical methodology in the available summary. Preclinical outcomes in rodents—including serum GPT reduction in LPS/D-GalN hepatotoxicity models and earthworm killing in anthelmintic assays—provide hypothesis-generating data but cannot establish clinical efficacy or safe dosing ranges for humans. Confidence in therapeutic benefit for any indication remains very low, and all traditional medicinal uses require prospective clinical validation before evidence-based recommendations can be made.
Safety & Interactions
No adverse effects, toxicity signals, or safety concerns have been formally documented in the available preclinical literature on Combretum quadrangulare; in vitro studies note that cytotoxic effects appear limited to targeted biological activities rather than nonspecific cellular toxicity, though systematic toxicological evaluation (LD₅₀, subchronic toxicity, genotoxicity) has not been published. Drug interactions have not been studied; however, the demonstrated alpha-glucosidase inhibitory activity of constituent flavonoids raises theoretical concern for additive hypoglycemic effects when combined with antidiabetic medications such as acarbose, metformin, or sulfonylureas, requiring monitoring if co-administered. The HIV-1 integrase inhibitory activity of extracts is a theoretical interaction concern with antiretroviral drugs (specifically integrase strand transfer inhibitors such as raltegravir or dolutegravir), though no pharmacokinetic or pharmacodynamic data exist to quantify this risk. Pregnancy and lactation safety are entirely uncharacterized; in the absence of any human safety data, use during pregnancy, lactation, or in pediatric populations cannot be recommended, and the maximum safe dose for any indication remains undefined.
Synergy Stack
Hermetica Formulation Heuristic
Also Known As
Combretum quadrangulare KurzSquare-stemmed combretumSakae naa (Thai)Combretaceae flavonoid herb
Frequently Asked Questions
What are the main active compounds in Combretum quadrangulare?
Combretum quadrangulare contains a rich array of polymethoxylated flavonoids including kumatakenin, ayanin, rhamnocitrin, ombuin, luteolin, apigenin, vitexin, isoorientin, mearnsetin, gardenin D, combretol, and multiple myricetin and quercetin methyl ethers isolated primarily from leaves. Additionally, a hepatoprotective gallic acid glycoside—O-galloyl-6-O-(4-hydroxy-3,5-dimethoxy)benzoyl-β-D-glucose—has been purified from methanolic extracts, and condensed tannins contribute to the plant's antioxidant and astringent traditional uses.
Does Combretum quadrangulare have any proven effects on blood sugar?
Preclinical in vitro studies show that flavonoids from C. quadrangulare, including ayanin, rhamnocitrin, and ombuin, inhibit the enzyme alpha-glucosidase with IC₅₀ values between 30.5 and 282.0 µM, which could theoretically reduce postprandial blood glucose by slowing carbohydrate digestion. Brominated synthetic analogues of these flavonoids were confirmed to act via noncompetitive inhibition through molecular docking studies, but no human clinical trials have tested blood sugar effects in diabetic patients, so evidence remains strictly preclinical.
Is Combretum quadrangulare safe to use as a supplement?
No formal human safety studies, toxicological evaluations, or clinical trials have been conducted on Combretum quadrangulare, meaning no established safe dose range, LD₅₀, or long-term safety profile exists for human use. In vitro preclinical data have not flagged overt cytotoxicity beyond targeted biological activities, but theoretical drug interaction concerns include additive hypoglycemic effects with antidiabetic medications and potential interference with HIV integrase inhibitor antiretroviral drugs; use during pregnancy or lactation is not recommended due to complete absence of safety data.
What does Combretum quadrangulare treat in traditional medicine?
In Thai traditional medicine, Combretum quadrangulare is used primarily for wound treatment and diarrhea management, with leaf decoctions and extracts applied topically or consumed internally. Vietnamese traditional practitioners additionally use the plant for hepatic complaints, febrile infections, and parasitic conditions, preparations including hot water decoctions and ethanolic extracts of leaves, roots, seeds, and stem bark depending on the therapeutic application.
How does Combretum quadrangulare compare to other antiplasmodial herbs?
Combretum quadrangulare ethanolic extracts show antiplasmodial activity against chloroquine-resistant Plasmodium falciparum K1 with IC₅₀ values of 1.25–4.0 µg/mL depending on plant part and solvent, which places it in a moderately active range comparable to other Combretum species and some Artemisia genus extracts evaluated in similar in vitro screens. However, unlike artemisinin-based compounds from Artemisia annua—which have undergone extensive clinical validation—C. quadrangulare has no human trial data, so its translational potential as an antimalarial agent remains speculative and requires pharmacokinetic and clinical investigation.
What is the evidence quality for Combretum quadrangulare's antimalarial effects?
In vitro studies demonstrate that methanolic stem extracts of Combretum quadrangulare show promising antiplasmodial activity against chloroquine-resistant Plasmodium falciparum, with IC₅₀ values of 1.25 µg/mL. However, clinical trials in humans are lacking, meaning current evidence is limited to laboratory research and traditional use reports rather than proven clinical efficacy. Further human studies are needed before it can be recommended as a standalone antimalarial treatment.
Who should avoid Combretum quadrangulare or use it with caution?
While traditional use in malaria-endemic regions suggests a safety history, pregnant women, nursing mothers, and individuals with severe liver or kidney disease should exercise caution due to limited safety data in these populations. People taking antimalarial medications should consult a healthcare provider before adding Combretum quadrangulare, as potential interactions have not been thoroughly studied. Children and the elderly may require dose adjustments pending more specific safety research.
How does the bioavailability of different Combretum quadrangulare extracts compare?
Methanolic and ethanolic extracts of Combretum quadrangulare leaves, roots, and stem bark have demonstrated different levels of antimalarial activity in laboratory settings, with stem bark extracts showing particularly strong potency. The choice of solvent (methanol, ethanol, or aqueous) affects which active compounds are extracted, potentially influencing absorption and efficacy. Standardized extracts targeting specific bioactive flavonoids may offer more consistent bioavailability than whole-plant preparations, though direct comparative bioavailability studies in humans are not available.
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