RESUMO
Noni (Morinda citrifolia) is a popular medicinal plant found in tropical or subtropical regions of the world. The fruit and juice extracts have properties that are reportedly therapeutic for diabetes, high blood pressure, and certain types of cancer (1,4). In our studies on noni juice produced from fruit collected from the Kohala and Puna districts of the island of Hawaii from 2008 to 2010, Mucor circinelloides f. sp. circinelloides was isolated from 85% of 157 juice samples and observed with up to 75% incidence on fruit surfaces during fermentation processing in glass jars. Fungal growth, appearing 14 to 21 days in storage at 22°C, was pale yellow to tan brown and was associated with wounded surfaces. Single-spore strains, KN 06-2 (2006; ripe fruit puree) and KN 08-08 (2008; fermented juice; CBS 124110), identified by Centraalbureau voor Schimmelcultures by molecular methods were 97.3% similar in internal transcribed spacer sequence to the type strain (CBS 195.68). M. circinelloides f. sp. circinelloides strains (KN 08-08, KN 09-06, or KN 10-02) (2008 to 2010; fermented juice) were inoculated by pipetting an aliquot of 100 µl of fungus strain spore suspension (1 × 105 to 1.33 × 106 spores/ml) onto firm, yellow maturity noni fruit that were washed, surface disinfected, and either wounded (surface cuts) or nonwounded. Controls consisted of no inoculation and sterile distilled water (SDW) inoculation treatments. Ten to twenty each of wounded and nonwounded fruit comprised each inoculation treatment. Fruit were incubated in acrylic bins with a layer of distilled water at the bottom, and sealed with snap-on lids. The bins were incubated on a lab bench at 22 to 23°C under fluorescent lights. Fruits were evaluated for presence of fungal growth and severity of symptoms. To determine viability of spores on inoculated fruit without symptoms, surfaces were swabbed with sterile cotton swabs dipped in SDW, streaked on potato dextrose agar (PDA) plates, and incubated at 22°C under fluorescent lights. The inoculation experiment was conducted twice. Nonwounded fruit inoculated with M. circinelloides f. sp. circinelloides strains did not result in infections (KN 09-06 and KN 10-02) or produced slight mycelial growth (0 to 20%; KN 08-08). Wounded fruit inoculated with any of the three strains resulted in 85 to 100% infection of moderate severity. There were no infections in noninoculated or SDW treatments of nonwounded or wounded fruit. Koch's postulates were fulfilled with the reisolation of M. circinelloides f. sp. circinelloides from selected fruit exhibiting soft tissue, discoloration, and sporulating yellowish green mycelial growth. Swab washes from asymptomatic surfaces of inoculated nonwounded fruit resulted in the growth of M. circinelloides f. sp. circinelloides on PDA, proving viability of the spores and confirmed that the fungus is primarily pathogenic only on wounded fruit surfaces. To our knowledge, this is the first report of M. circinelloides as a wound pathogen of noni fruit. The quality of fermented noni juice may be affected by the presence of M. circinelloides f. sp. circinelloides but can be remedied by pasteurization that does not affect antitumor properties (unpublished data). This fungus is also a reported pathogen of mango (2) and peach (3). References: (1) J. Li et al. Oncol. Rep. 20:1505, 2008. (2) K. Pernezny and G. W. Simone. Phytopathol. News 34:25, 2000. (3) C. Restuccia et al. J. Food Prot. 69:2465, 2006. (4) M. Y. Wang et al. Acta Pharmacol. Sin. 23:1127, 2002.
RESUMO
Noni has been extensively used in folk medicine by Polynesians for over 2000 year. Recent studies have shown that noni has a wide spectrum of therapeutic activities including inhibition of angiogenesis, anti-inflammatory effects and anti-cancer activities. Intraperitoneal (i.p.) injection of fermented noni exudates (fNE) were previously found to induce significant tumor rejection in a S180 mouse sarcoma tumor model, while natural killer (NK) cells were demonstrated to be markedly involved in fNE-induced antitumor activity. In this study, fNE was partitioned into three fractions and their antitumor effects were examined using i.p. injection or as water supplement. The in vivo animal study results showed that when delivered by i.p. injection, n-butanol fraction of fNE (BuOH) effectively rejected (100%) tumor challenge and eradicated existing tumors (75%). When delivered as a water supplement, 62.5% of the mice receiving the n-butanol or ethyl acetate fractions resisted tumor cells. The tumor-resistant mice effectively rejected more and higher doses of tumor challenge, indicating that the immune system was activated. The findings confirm those of an earlier study showing fNE to have anti-tumor activity and demonstrating that the n-butanol fraction of fNE contains active antitumor components, to be further identified. More importantly, the antitumor effect of fNE and its fractions as water supplements renders a significant potential for identifying novel and powerful new dietary products for cancer prevention.