Tetrandrine (Bisbenzylisoquinoline Alkaloid · Anti-fibrotic · Calcium Channel)

Compound	Tetrandrine
Chemical class	Alkaloid — Isoquinoline (Bisbenzylisoquinoline)
CAS	518-34-3
Primary source	Stephania tetrandra (Han Fang Ji / Chinese stephania root)
Key applications	Anti-inflammatory, anti-fibrotic, calcium channel blockade, antihypertensive
Claim strength	Moderate
Typical form	Stephania tetrandra root extract; tetrandrine isolate
Buy from Herbuno	Request availability and bulk pricing →

Commercial source: Tetrandrine is commercially available as an extract from Stephania tetrandra root from specialist botanical suppliers, and as an isolated alkaloid from specialist chemical suppliers. Concentrated tetrandrine extract for supplement use requires specialist sourcing. Contact Herbuno for availability assessment. Traditional use: Stephania tetrandra (Han Fang Ji, “fang ji” in TCM) has been used in TCM for over 2,000 years for oedema management, rheumatic joint conditions, urinary tract disorders, and hypertension. Han Fang Ji is one of the classic anti-oedematous herbs in TCM pharmacopoeia. Tetrandrine is identified as the primary alkaloid responsible for these properties. Research trajectory: Tetrandrine has a substantial evidence base from Chinese research for anti-inflammatory, calcium channel-blocking, anti-fibrotic (particularly silicosis/pulmonary fibrosis), and antihypertensive mechanisms. It has been studied clinically in China for silicosis and cardiovascular conditions. Concerns about nephrotoxicity from adulterated or substituted fang ji preparations have affected regulatory perceptions in Western markets. See sourcing options below.

---

Evidence for Tetrandrine Applications

Calcium channel blockade and antihypertensive: Tetrandrine is an L-type calcium channel blocker with antihypertensive activity in animal models and small Chinese human studies. Its calcium channel blocking mechanism is relevant to cardiovascular formulations for blood pressure support. Claim strength: Moderate.

Anti-fibrotic (silicosis/pulmonary fibrosis): Chinese clinical studies of tetrandrine for silicosis — inflammatory lung fibrosis from silica dust exposure — demonstrate reduced fibrosis progression and improved lung function scores. This is one of the more specific botanical pharmaceutical applications globally. TGF-β pathway inhibition and myofibroblast differentiation suppression are the primary anti-fibrotic mechanisms. Claim strength: Moderate (Chinese clinical evidence; Western RCTs absent).

Anti-inflammatory: Tetrandrine inhibits NF-κB, reduces inflammatory cytokine production, and suppresses NLRP3 inflammasome activation in macrophage and joint cell models. Anti-inflammatory activity in arthritis animal models is well-documented, consistent with Han Fang Ji traditional rheumatic use. Claim strength: Moderate.

---

Dosage & Formulator Specification

TCM Han Fang Ji dose: 5–10 g/day dried root. Chinese pharmaceutical tetrandrine for silicosis: 60–120 mg/day oral. For supplement applications, Stephania tetrandra extract at 200–500 mg/day standardised to tetrandrine content (typically 2–5% tetrandrine by HPLC) is a working range for anti-inflammatory and cardiovascular applications. Contact Herbuno for Stephania tetrandra extract availability.

Critical adulteration warning: Stephania tetrandra (Han Fang Ji) has historically been adulterated with Aristolochia fangchi (Guang Fang Ji) in Chinese herbal preparations. Aristolochia species contain aristolochic acid — a potent nephrotoxin and carcinogen responsible for multiple cases of severe kidney failure (“Chinese herb nephropathy”) in Europe and elsewhere. This adulteration was the cause of a significant international health scandal in the 1990s. Formulators must require strict botanical identity verification (DNA barcoding, macroscopic examination, HPLC alkaloid profile confirming tetrandrine/fangchinoline without aristolochic acid) for all Stephania tetrandra materials. Aristolochic acid testing (<0.1 ppb by LC-MS) must be included in the CoA specification for any fang ji product.

---

Frequently Asked Questions — Tetrandrine

Is tetrandrine safe given the aristolochic acid adulteration history?
Tetrandrine itself, from verified Stephania tetrandra source, does not contain aristolochic acid and is not nephrotoxic at the compound level. The nephrotoxicity episodes were caused specifically by substitution or adulteration with Aristolochia species — a different plant genus. However, the adulteration risk is serious enough that rigorous botanical identity verification is non-negotiable for any fang ji product. Formulators must specify and verify S. tetrandra identity and aristolochic acid testing for every batch.

What is the difference between Han Fang Ji and Guang Fang Ji?
Han Fang Ji is Stephania tetrandra — a legitimate TCM herb containing tetrandrine and fangchinoline as bisbenzylisoquinoline alkaloids (non-toxic at therapeutic doses). Guang Fang Ji is Aristolochia fangchi — a different plant containing aristolochic acid, a nephrotoxin and carcinogen. Both were historically used in TCM under the general “fang ji” label, leading to dangerous adulteration. Current Good Procurement Practice requires clear differentiation and verification.

Does tetrandrine have significant CYP enzyme inhibition?
Tetrandrine inhibits CYP3A4 and P-glycoprotein in vitro at concentrations achievable at therapeutic doses. This creates potential drug interaction concerns with medications metabolised by CYP3A4 (statins, cyclosporine, some antivirals). Standard advisory language for CYP3A4-metabolised medications is appropriate for any tetrandrine-containing product.

Is tetrandrine being investigated for COVID-19 or antiviral applications?
Yes — tetrandrine attracted attention during the COVID-19 pandemic for its calcium channel-blocking activity relevant to viral membrane fusion inhibition. In vitro studies showed inhibition of SARS-CoV-2 entry. This is an emerging application area. No clinical trials have been completed for tetrandrine in COVID-19 specifically, but the antiviral mechanistic rationale has been documented.

---

Claim-strength scale – High = multiple human RCTs; Moderate = limited trials or strong preclinical convergence; Emerging = early-stage lab or animal data.

← HerbIQ Compound Index · HerbIQ P02: Extraction · HerbIQ P03: Delivery