Multi-omics and palynology of selected Philippine forest honey.

The Sierra Madre Mountains, which happen to be the longest mountain range in the Philippines, is home to lush floral and faunal species as well as forest-based indigenous communities actively involved in preserving local biodiversity. With active reforestation efforts ongoing for decades, the locals are further encouraged to continue their long-standing practice of honey gathering as a form of cultural manifestation and as an important source of livelihood. To further inspire ongoing conservation efforts, we aim to show that the small molecule diversity in Sierra Madre forest honey reflects the local floral composition and is reflective of the positive impact of previous reforestation initiatives. In order to do this, liquid chromatography-mass spectrometry (LC-MS) based metabolomics was used to profile and compare metabolite diversity in honey produced by Apis cerana, Apis breviligula Maa. and Tetragonula biroi (Friese) honey from Palaui Island and Laiban in Northern and Southern Sierra Madre, respectively. Surprisingly, the Philippine National Tree and unfortunately endangered Pterocarpus indicus Willd (loc. Narra) proved to be important, especially in Palaui Island where honey from A. cerana is close to being monofloral. Aside from P. indicus and its small molecule marker hypaphorine, caffeine was detected in Palaui honey beautifully reflecting the way of life of native Agtas who manage a small coffee plantation. The abundance of caffeine, however, is higher in stingless honey samples from Tanay, Rizal where Coffea trees have been extensively included in restoration activities over the past few decades. Our results imply the possibility of using honey as an ecological monitoring tool while generating baseline chemical information that reflects the state of Philippine forests. Furthermore, the identification of unique chemical components in forest honey can be further used in programs that assist indigenous communities in safeguarding the ownership and origin of forest honey sources.