Scientific analysis of indigenous techniques for guggal (Commiphora wightii) tapping in India

Guggal, a threatened species that is endemic to western India, is tapped to extract medicinally important oleo-gum-resin (guggul). However, the plant dies after gum exudation. The indigenous tapping techniques used by local people were examined in Gujarat, India to dis- cover the scientific basis behind these techniques: selection of gum in- ducer, season of tapping, and plant parts to be tapped. First, the presence of Xanthomonas axonopodis pv. commiphorae (Xac) in the gum suspen- sion used for tapping was established. This bacterium induces gum ooz- ing from the tapped plants and later, causes them to die off. The popula- tion of Xac in gum was found to decrease with the age of the gum. With that, fresh gum increased the tapping success. Second, local people pre- ferred tapping during the warm season, which we validated by determin- ing that Xac growth was best at 30 °C. Tapping during September (mean temperature 25.7-30.0 °C) clearly favoured growth of the pathogen and yielded maximum guggul. Multiple tapping on a mature tree ensured maximum gum extraction before its death. Finally, application of in- digenous technology under natural plant stands by the local people en- sured availability of this important raw drug for consumption. Our study established that the age-old traditional methods have a strong scientific basis. However, it is imperative to formulate strategies based on con- temporary scientific understanding to protect this natural resource before it becomes extinct.