Tong Cao

Phytochemical isolation from the pith, which is the drug Medulla Tetrapanacis rather than any other organ of the plant. Two new steroidal ketones were characterised along with ten known steroids and five steroidal saponins, thirteen of them reported from Tetrapanax papyriferus for the first time. Chemistry only; no biological testing, so it establishes what the drug contains without saying what any of it does.

Isolated four previously undescribed and four known oleanane-type triterpenes from Tetrapanax papyriferus, sampling flowers, pith, leaves and fruit. Papyriogenin A showed anti-HIV activity with low cytotoxicity in acutely infected H9 lymphocytes. The anti-HIV result is a single in vitro finding for one purified compound and does not transfer to a decoction of the pith.

Forty-two rats with chronic constriction injury of the sciatic nerve were randomised to sham, injury, pregabalin, mecobalamin, Tetrapanax papyriferus or hederagenin. Both Tetrapanax and hederagenin reduced mechanical, thermal and cold hypersensitivity, lowered serum IL-1 beta, IL-6 and TNF-alpha, and reduced dorsal root ganglion TRPM8, TRPA1, TRPV1, TRPV4 and phosphorylated p38 MAPK. The rationale was that Tetrapanax is a component of Danggui Sini decoction. The report does not state which plant part the Tetrapanax preparation came from, so it cannot be assumed to describe the pith specifically.

GC-MS and GC-FID identified 61 compounds in the essential oil, 96.05 per cent sesquiterpenoids, led by beta-cubebene, caryophyllene and alpha-cubebene. Antioxidant IC50 values were 723.15 micrograms per millilitre for DPPH and 200.74 for ABTS, and alpha-glucosidase inhibition reached only 17.86 per cent at 500 micrograms per millilitre. Weak in vitro activity at concentrations far above anything a decoction of dried pith would produce.

Review of the toxicity of Aristolochia manshuriensis, the Guan Mu Tong sold under the commercial name Mu Tong, documenting nephrotoxicity and the clinical picture of aristolochic acid nephropathy. Included here because Mu Tong is the drug that the classical name Tong Cao denoted, so the two names sit at opposite ends of a safety spectrum: an inert pith and an established human nephrotoxin and carcinogen.

Develops a loop-mediated isothermal amplification assay that separates the official Akebiae Caulis from the toxic adulterant Aristolochiae Manshuriensis Caulis. The paper documents that Mu Tong sold in trade may be Aristolochia manshuriensis and that consumers taking adulterated Guan Mu Tong risk renal failure and upper tract urothelial carcinoma, which is why a DNA-level test was needed at all.