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Alotaibi et al. J Cancer Metastasis Treat 2017;3:161-8 Journal of
DOI: 10.20517/2394-4722.2017.33
Cancer Metastasis and Treatment

www.jcmtjournal.com
Original Article Open Access

Papaya black seeds have beneficial anticancer

effects on PC-3 prostate cancer cells

Khalid S. Alotaibi , Haiwen Li , Reza Rafi , Rafat A. Siddiqui 2
3
1
2
1 Department of Biology, Virginia State University, Petersburg, VA 23806, USA.
2 Nutrition Science and Food Chemistry Laboratory, Agriculture Research Station, College of Agriculture, Virginia State University, Petersburg, VA 23806, USA.
3 Agriculture Research Station-Cooperate Extension, College of Agriculture, Virginia State University, Petersburg, VA 23806, USA.
Correspondence to: Dr. Rafat A. Siddiqui, Nutrition Science and Food Chemistry Laboratory, Agriculture Research Station, College of
Agriculture, Virginia State University, Petersburg, VA 23806, USA. E-mail: rsiddiqui@vsu.edu
How to cite this article: Alotaibi KS, Li H, Rafi R, Siddiqui RA. Papaya black seeds have beneficial anticancer effects on PC-3 prostate cancer cells.
J Cancer Metastasis Treat 2017;3:161-8.
ABSTRACT
Article history: Aim: The study investigated the effect of papaya seeds on prostate cancer (PC) using
Received: 20-05-2017 PC-3 cell line because papaya seeds have effects on the male reproductive system notably
Accepted: 11-08-2017 decreasing sperm concentration, motility, and viability, leading to azoospermia after
Published: 28-08-2017 short-to-long-term treatment. Methods: The black seeds from yellow (ripe) papaya and
white seeds from green (unripe) papaya were harvested and then extracted in water, 80%
Key words: methanol, and hexane. The cytotoxic effects of seeds extracts were determined using a
Papaya, WST-1 proliferation assay. The amount of total polyphenols was determined using Folin
seeds, Ciocalteu reagent. Results: The methanol extracts from black seeds significantly (P <
prostate cancer, 0.05) decreased cell proliferation of PC-3 cells whereas hexane- and water-extracts have
polyphenols
no effect. However, the water-extract from white seeds stimulated PC cell proliferation.
The black seeds contained significantly more polyphenols than that of white seeds. The
data suggest that black seeds from papaya have anticancer effects on PCs whereas white
seeds stimulated prostate cancer proliferation. The anticancer effect of black seeds may
be because of their high concentration of polyphenols. Conclusion: The black seeds from
papaya may have a potential to reduce growth of prostate cells; however, consumption of
white seeds should be avoided as they may stimulate pre-existing prostate cancer.

INTRODUCTION reported worldwide and nearly half-8.2 million people
(about 13% of the total worldwide deaths) died from
The prostate cancer is the malignant tumor of the cancer. The cases of cancer is expected to increase
[2]
prostate gland of male reproductive organ, which may to 24 million by 2035, therefore, the death toll from
be life threatening, when spread to other body parts, cancer is expected to increase in the future.
predominantly towards lymph nodes, and bones. [1]
According to a report (2014) published by Cancer The major factor contributing in prostate cancer is the
Research, UK, an estimated 14 million cases of cancer age, because men who have the prostate cancer are

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