Corosolic Acid (Triterpenoid)

Corosolic acid is a pentacyclic triterpenoid found in banaba leaves that inhibits protein-tyrosine phosphatase 1B with IC₅₀ values of 3.6-29.1 μM. This compound may support blood sugar regulation and weight management through enhanced glucose uptake and insulin sensitivity.

Origin & History

Corosolic acid is a pentacyclic triterpenoid (C₃₀H₄₈O₄) primarily extracted from the leaves of Lagerstroemia speciosa (banaba tree), structurally similar to ursolic acid but with a 2-alpha-hydroxy group. It is also found in guava, loquat, olive, apples, basil, bilberries, cranberries, and prunes, and is typically isolated as a powder standardized to ≥98% purity via HPLC.

Historical & Cultural Context

The research provides minimal historical context, noting only that corosolic acid is registered as a dietary supplement for diabetes in modern contexts. No information about traditional medicine systems or historical use duration is available in the current research dossier.

Health Benefits

• Potential blood sugar regulation through protein-tyrosine phosphatase 1B inhibition (IC₅₀ 3.6-29.1 μM) - based on preclinical studies only
• May support weight management and reduce hepatic steatosis - shown in KK-Ay mouse models, no human data
• Possible anti-inflammatory effects through NF-κB pathway modulation - preclinical evidence only
• Potential antitumor activity via β-catenin degradation and STAT-3 inhibition - demonstrated in colon cancer cell lines
• May improve lipid metabolism - suggested by preclinical data on pentacyclic triterpenoids

How It Works

Corosolic acid inhibits protein-tyrosine phosphatase 1B (PTP1B), an enzyme that negatively regulates insulin signaling pathways. By blocking PTP1B activity, corosolic acid enhances insulin receptor phosphorylation and promotes glucose transporter 4 (GLUT4) translocation to cell membranes. The compound also suppresses NF-κB signaling pathways, potentially reducing inflammatory cytokine production.

Scientific Research

The research dossier reveals a concerning lack of human clinical trials for corosolic acid, with no RCTs, meta-analyses, or PubMed PMIDs for human studies provided. All available evidence comes from preclinical studies in animal models (KK-Ay mice) and cell lines, limiting the ability to make evidence-based claims about human health benefits.

Clinical Summary

Current evidence for corosolic acid is limited to preclinical studies and animal models. In vitro studies demonstrate PTP1B inhibition with IC₅₀ values ranging from 3.6-29.1 μM depending on the assay conditions. KK-Ay diabetic mouse studies showed improvements in glucose tolerance and reduced hepatic steatosis, but no human clinical trials have been published. The lack of human data significantly limits conclusions about therapeutic efficacy and optimal dosing.

Nutritional Profile

Corosolic acid (2α,3β-dihydroxyurs-12-en-28-oic acid) is a pentacyclic triterpenoid with molecular formula C₃₀H₄₈O₄ and molecular weight 472.7 g/mol. It is not a macronutrient or micronutrient source itself but rather a bioactive phytochemical. Key profile details: • Found naturally in Lagerstroemia speciosa (banaba) leaves at concentrations of approximately 0.5–1.5% dry weight, also present in Eriobotrya japonica (loquat) leaves (~0.02–0.08% dry weight), Vaccinium myrtillus (bilberry), apple peels (~40–100 µg/g dry weight), and Weigela subsessilis. • As a single triterpenoid compound, it contains no protein, fiber, vitamins, or minerals. Its caloric contribution in typical supplemental doses (0.5–10 mg/day) is negligible. • Structural features: ursane-type skeleton with hydroxyl groups at C-2α and C-3β positions and a carboxylic acid at C-28; the 2α-hydroxyl distinguishes it from ursolic acid and is critical for its PTP1B inhibitory activity. • Bioavailability: Oral bioavailability is relatively low due to poor aqueous solubility (log P ~6.8, practically insoluble in water). Absorption is enhanced when administered with lipid-based carriers or as part of a standardized banaba leaf extract containing mixed triterpenoids and ellagitannins. First-pass hepatic metabolism involves Phase I oxidation (CYP450-mediated) and Phase II glucuronidation. Plasma half-life in rodent models is estimated at 4–8 hours. • Typical supplemental dose in banaba leaf extracts standardized to 1% corosolic acid is 32–48 mg extract (delivering ~0.32–0.48 mg corosolic acid) taken 1–3 times daily; some studies use up to 10 mg pure compound. • Co-occurring bioactives in natural sources that may contribute to synergistic activity include ellagic acid, gallotannins (lagerstroemin), valoneic acid dilactone, and other ursane/oleanane-type triterpenoids (maslinic acid, oleanolic acid, ursolic acid at comparable or lower concentrations in banaba leaf).

Preparation & Dosage

No clinically studied dosage ranges for humans are available in the current research. Commercial products typically contain corosolic acid standardized to ≥98% purity from Lagerstroemia speciosa extracts. Consult a healthcare provider before starting any new supplement.

Synergy & Pairings

Chromium picolinate, Alpha-lipoic acid, Cinnamon extract, Gymnema sylvestre, Bitter melon extract

Safety & Interactions

Safety data for corosolic acid supplementation in humans is limited due to lack of clinical trials. The compound may potentially interact with diabetes medications by enhancing glucose-lowering effects, requiring blood sugar monitoring. Pregnant and breastfeeding women should avoid corosolic acid supplements due to insufficient safety data. No specific adverse effects or drug interactions have been documented in available literature.