Lichens in the Philippines: diversity and applications in natural product research

The Philippine archipelago owing to its geographical location and tropical climatic condition is undeniably rich in biodiversity, yet it remains as one of the underexplored countries for the study on lichen flora. This chapter revisits the early works on Philippine lichens and compiled recent studies dedicated to the exploration of their biodiversity and bioactivities. We highlighted the effectiveness of their secondary metabolites against different microorganisms, particularly those that cause serious human health problems and diseases of agricultural crops, and suggested lichens as prospective candidates for natural product research. Furthermore, this chapter also introduces endolichenic fungi, a group of nonexpressive symptom fungi inhabiting the lichen thalli, which are reported for the first time in the country as alternative sources of valuable bioactive secondary metabolites. With this chapter, we hope that more researches will be encouraged to study Philippine lichens and fill in the large gaps in the exploration of our lichen diversity and natural product research.