An ethnobotanical approach to control Typha angustifolia: A case study from Sri Lanka

Abstract

Typha is a cosmopolitan genus that is infamous globally for having nuisance plant species. In Sri Lanka, Typha angustifolia is distributed in both coastal and inland wetlands, including lagoons, paddy fields, and small reservoirs. Pervasive effects of Typha include hindrance to fishing activities, navigation, agriculture, human health, and ecosystem functions, especially provision of habitats for wading birds in coastal lagoons. The present study attempted to formulate an ethnobotanical strategy to control the distribution of Typha in Embilikala lagoon in Bundala National Park in Hambantota District in Southern Sri Lanka. T. angustifolia edible plant parts were tested for antioxidant activity to promote it as a phytonutrient that boosts the overall health of the body. Hexane, methanol, and aqueous extracts of leaf, leaf base, rhizome, and pollen of Typha were analyzed with DPPH and ABTS bioassays for the presence of antioxidants. Leaves were tested for their quality as raw material for making paper using the mould and deckle pouring method and couching technique. Methanol was found to be superior to hexane and deionized water as a solvent for both the assays. Leaf base (99.5±5.3 μg/mL) and rhizome (65.3±0.6 μg/mL) of T. angustifolia showed higher radical scavenging activity, and in some instances, higher than that of standard butylated hydroxytoluene (BHT) (119.3±4.5 μg/mL), indicating their potential as sources of bioactive compounds that can reduce free radicals. Contents of heavy metals (Arsenic: 0.338±0.040, Cadmium: 0.628±0.146, Chromium: 63.641±1.30, Lead: 15.657±1.70 ppb) in the rhizomes were below the standard permissible level (100.0 ppb). Pulp made with Typha leaves alone and a mixture of Typha (95%) and wastepaper (5%) were used successfully to produce writable paper. Findings suggest that T. angustifolia, which is widely considered as an invasive plant and marginally utilized currently, has a promising potential to be exploited as food and raw material to introduce new livelihoods to rural communities. This ethnobotanical approach may potentially be used to control the distribution of T. angustifolia in wetlands where it is found in invasive proportions.