**4. Conclusions**

The findings from the present study indicate that the total polyphenols, carotenoids and antioxidant capacity of selected green leafy vegetables are significantly altered during common cooking practices such as boiling, steaming, and frying. Among the cooking methods evaluated, frying reduces the polyphenols, flavonoids, carotenoids, and antioxidant activities in all leafy vegetables studied, whereas boiling and steaming have shown varying effects on polyphenols, carotenoids, and antioxidant properties, depending on the leafy type. The results of the study can be used for making recommendations on the food processing methods to be chosen for preserving the health benefits of green leafy vegetables.

**Author Contributions:** K.D.P.P.G. performed all the experiments, analyzed the data, and wrote the manuscript. All the authors contributed to the designing of the experiments and proofreading the manuscript.

**Funding:** We greatly acknowledge the financial support provided by the National Science Foundation of Sri Lanka (NSF) (Research Grant # RG/AG/2014/04).

**Acknowledgments:** We thank H.P.S. Jayaweera of the Wayamba University of Sri Lanka for their technical support.

**Conflicts of Interest:** The authors declare no conflict of interest.
