The short version
- Cisplatin, a chemotherapy drug, can damage hearing, and in this mouse study it raised high-pitch hearing thresholds by about 24 dB.
- Mice given honokiol, a compound from magnolia, an hour before each dose showed no significant hearing loss and kept their inner-ear connections.
- It is a mouse study with patent-holding authors and no human data, so it says nothing yet about people on chemotherapy.
Researchers at Northwestern University’s Feinberg School of Medicine report that honokiol, a compound found in magnolia trees, protected hearing in mice receiving cisplatin, a chemotherapy drug known to damage the inner ear. Female mice with breast tumors got three 14-day cycles of cisplatin, some with an injection of honokiol at 5, 10 or 20 mg/kg an hour before each dose. Groups held 9 to 21 mice. By day 42, cisplatin alone had raised hearing thresholds at 32 kHz, a very high pitch, by 23.6 dB. In the honokiol groups the shift was not statistically significant at any frequency tested. The connections between inner hair cells and nerve fibers fell from about 15 per cell to 12 on cisplatin alone and stayed near 15 with honokiol. The paper appeared in Pharmaceuticals on October 12.
The authors list the limits themselves. Hearing loss was milder than in earlier work using the same regimen, possibly because a strict weight-loss cutoff took the worst-affected mice out early. Survival differences between groups were not significant. The protein changes they measured are not yet shown to cause the protection, and only one tumor model was tested. Two authors are inventors on a related Northwestern patent. Honokiol is also sold as a supplement, and nothing here tests that use.
There are no human data yet.
