Brown coal derived humate inhibits contact hypersensitivity; an efficacy, toxicity and teratogenicity study in rats.
OBJECTIVE
The effects of two humate products were compared to that of prednisolone on a contact hypersensitivity rat model.


METHODS
Rats, sensitized with dinitrofluorobenzene (DNFB), were placed on a daily oral treatment of 61 mg/kg BW of humate derived from either leonardite or bituminous coal or on prednisolone at one mg/kg BW and challenged 6 days later with a topical application of DNFB to the right ear. The inflamed ears were measured daily. In a toxicity study rats were exposed to daily oral treatment of leonardite humate at 1,000 mg/kg BW for 1 month. A teratogenicity study was done where pregnant rats were treated with 500 mg/kg BW on days 5 to 17 of pregnancy.


RESULTS
Only the leonardite humate compared favourably with prednisolone in suppressing contact hypersensitivity. No signs of toxicity were observed and weight gain was normal during the 6-day and 1 month treatments and during the teratogenicity study with the leonardite humate. However, the rats on the other two products experienced slower weight gain.


CONCLUSIONS
The identification of a naturally occurring nontoxic compound with anti-inflammatory activity is exciting and merits further evaluation in the treatment of patients suffering from inflammatory conditions.
Van Rensburg
C E J
CE
Department of Pharmacology, Faculty of Health Sciences, University of Pretoria, PO Box 2034, Pretoria, 0001, South Africa. cmedlen@postillion.up.ac.za
Snyman
J R
JR
Mokoele
T
T
Cromarty
A D
AD
D000014:Abnormalities, Drug-Induced / Q000209:etiology; D000284:Administration, Oral; D000818:Animals; D000893:Anti-Inflammatory Agents / Q000008:administration & dosage / Q000494:pharmacology* / Q000633:toxicity; D001835:Body Weight / Q000187:drug effects; D003031:Coal; D003877:Dermatitis, Contact / Q000209:etiology / Q000517:prevention & control*; D004139:Dinitrofluorobenzene; D004195:Disease Models, Animal; D005260:Female; D005333:Fetus / Q000187:drug effects; D006812:Humic Substances / Q000633:toxicity; D011239:Prednisolone / Q000494:pharmacology; D011247:Pregnancy; D051381:Rats; D017207:Rats, Sprague-Dawley; D013997:Time Factors
D000893:Anti-Inflammatory Agents; D003031:Coal; D006812:Humic Substances; D011239:Prednisolone; D004139:Dinitrofluorobenzene