178 Papaya
16.2.6 Antibiotic Activity
The extracts of ripe and unripe papaya fruits and of the seeds are active against Gram-
positive bacteria. Strong doses are effective against Gram-negative bacteria. The
substance has protein-like properties. The fresh crushed seeds yield the aglycone of
glucotropaeolin benzyl isothiocyanate (BITC), which is bacteriostatic, bactericidal
and fungicidal. A single effective dose is 5 g seeds (25–30 mg BITC) for the same.
Papaya was also found to be effective in curing postoperative infection in a kidney
transplant patient by strip laid on the wound and left for 48 h.
16.2.7 Anti-Cancer Activity
The fibre of papaya is able to bind cancer-causing toxins in the colon and keep them
away from the healthy colon cells. These nutrients provide synergistic protection for
colon cells from free radical damage to their DNA (Desser et al. 2011). Men con-
suming fruits were 82% less likely to have prostate cancer compared to those con-
suming the least lycopene-rich foods. An in vitro study using the extract of the seed
homogenate was highly effective in inhibition of superoxide generation and inducing
apoptosis in acute promyelocytic leukaemia cell line HL-60 and the activity was
mainly contributed by benzyl isothiocyanate (BITC) (Nakamura et al. 2007). The
BITC isolated from the papaya fruit extract induced cytotoxic effect in proliferating
human colon CCD-18Co cells to the quiescent state (Miyoshi et al. 2007). The aque-
ous extract of Carica papaya exposed to onion bulbs disturbed the mitotic cell divi-
sion of Allium cepa by affecting the spindle formation and hence shows its cytotoxic
effect (Akinboro and Bakare 2007). The aqueous extract of papaya flesh (0.01%–
4.00% v/v) treated with breast cancer cell line, MCF7 revealed significant inhibi-
tion of cell proliferation (García-Solis et al. 2009). The aqueous extract of papaya
leaves in an unrevealed composition is shown to possess anticancer activity and
inhibition of cell proliferation in a variety of cancer cell lines, which has been pat-
ented by Morimoto et al. (2008). Likewise, the aqueous extract demonstrated antitu-
mour activity and immunomodulatory activity in tumour cell lines and it proved up
regulation of immunomodulatory genes by microarray studies (Otsuki et al. 2010).
However, further investigation using cell culture studies, animal studies and clinical
trials is needed for proving the chemoprevention and therapeutic potential of differ-
ent papaya plant parts and check the adverse effects, if any, in consumption of some
parts of papaya (Nguyen et al. 2013).
16.2.8 anti–rheumatoid arthritiS activity
Vitamin C-rich foods, such as papaya, provide humans with protection against
inflammatory polyarthritis, a form of rheumatoid arthritis involving two or more
joints (Aravind et al. 2013).
16.2.9 Anti-Dengue Activity
A case report from Pakistan (Ahmad et al. 2011) documented that aqueous extract
of C. papaya leaves administered to a patient affected with dengue fever twice