Abstract
Aim: This thesis investigates the potential of mamaku (Cyathea medullaris) as an intraoral medicament by exploring its ethnobiology and examining its extraction technology, bioactivity and interactions with human gingival fibroblasts (HGF-1). The goal was to determine the therapeutic efficacy and biocompatibility of mamaku extracts for oral health applications.
Method: The research is divided into four main areas: 1) narrative review exploring the ethnobiology of mamaku; 2) Extraction Technology: Various extraction methods were employed to isolate mamaku polysaccharides, including vacuum-filtered crude mamaku (VFCM), centrifuge-filtered crude mamaku (CFCM) and purified polysaccharide (PS); 3) Bioactivity and Rheology: Experiments assessed the gelling behaviour, rheological properties and antimicrobial effects of mamaku extracts. Scanning electron microscopy (SEM) was used to analyse the physical structure of freeze-dried constructs; 4) Cell Biology and In vitro Modelling: The effects of mamaku on cell attachment, viability and cytotoxicity were studied using HGF-1 cells. Different concentrations of mamaku were tested to determine their impact on cell health. An in vitro model simulating the gingival pocket environment was used to evaluate the substantivity and degradation of mamaku gels.
Results: Ethnobiology: Mamaku is a regenerative fern that has been used for over a century. Māori use mamaku in rongoā rākau (traditional herbal medicine) showing the potential to heal the body and the forest. Extraction Technology: VFCM was identified as the most promising extract due to its bioactive properties and alignment with traditional uses. Bioactivity and Rheology: Mamaku polysaccharides demonstrated shear-thinning and thixotropic properties, making them suitable for controlled release and bio-adhesive applications. The 30% VFCM gel exhibited robust gel structures with comparable properties to commercial oral healthcare products. Cell Biology and In vitro Modelling: Lower concentrations of mamaku supported cell viability, while higher concentrations showed cytotoxic effects. The Transwell system provided a nuanced understanding of the effects of mamaku on cell viability. The 30% VFCM gel showed significant mass loss under simulated intraoral conditions, indicating potential increased bioavailability and efficacy.
Conclusion: Mamaku polysaccharides hold promise as intraoral medicaments, with potential applications in oral health care. The innovation process benefited from considering mātauranga Māori alongside modern scientific methods in developing natural, biocompatible therapies. Further optimisation of mamaku formulations is necessary to maximise therapeutic benefits and minimise adverse effects.