Insights into the effectiveness of synthetic and natural additives in improving biodiesel oxidation stability

•Natural extracts (e.g. ginger, basil) are potentially greener biodiesel additives.•Lack of natural antioxidants studies compared to synthetics like BHA, BHT, TBHQ.•Complexity of natural antioxidants is a challenge in antioxidant studies.•Purification of antioxidant compounds in natural extracts is needed.•Oxidation kinetics and thermodynamics of antioxidants yet to be elucidated.