# An Analysis of Commercial Noni Juice: LC-MS/MS Phenolic Profiles and Cytotoxic Activity
## 3 Results and Discussion
### Quantitative Phenolic Profiling by LC-MS  
Targeted LC-MS profiling of the noni juice samples revealed the presence of 21 phenolic compounds putatively identified across all five noni juice brands. Most of these compounds (14) were common to all samples, while several were only found in one or two samples (e.g., neochlorogenic acid, cyanidin 3-glucose, sinapic acid, ellagic acid, kaempferol). Figure 2 shows the chromatogram traces for one of the noni juice samples overlaid with the combined standards solution, at a wavelength of 254 nm. The phenolic profiles varied markedly between the various brands. The most abundant compound in three of the brands (TON, DHN and LHN) was ruin (6.8-41.2 mg L\({}^{-1}\)). In contrast, the CIN brand showed virtually no ruin (0.09 mg L\({}^{-1}\)). Similar differences were observed between brands for most of the detected phenolic compounds (Table 6). This agrees with the results of [PERSON] et al. [17], who observed a high level of variation in seven phenolic constituents between eight brands of noni juice produced in China, Taiwan and Fiji. Similarly, [PERSON] et al. [31] observed that the processing methods had a significant impact on the total phenolic content and bioactivity of noni juice samples. Consequently, it is likely  
Figure 2: LC-MS chromatogram at 254 nm showing the location of selected phenolic peaks identified in one of the noni juice samples (FN = Fijiian Noni). The numbered peaks correspond to the compound numbers in Table 3. \begin{table}
\begin{tabular}{c c} \hline \hline
**Noni juice** & **\% Inhibition** \\ \hline FN & 26.4\% \\ LHN & 18.4\% \\ DHN & 9.6\% \\ TON & 20.3\% \\ CIN & 30.2\% \\ \hline \hline \end{tabular} Abbreviations: FN = Fijiian Noni; LHN = Life Health Noni; DHN = Dynamic Health Noni; TON = Tahitian Organic Noni; CIN = Cook Island Noni.  
\end{table} 
Table 5: Acetylcholinesteraseterase (AChE) inhibitory activity of the neat noni juice samples. Values are given as the percentage of total inhibition. that this high level of variation in composition between brands can be attributed to the different starting materials and processes used in their manufacture. All six of the phenolic compounds reported by [PERSON] et al. [17] were also detected in this work (gentisic acid, caffe acid, \(p\)-coumaric acid, ferulic acid, sinapic acid and quercetin). Additional compounds reported here include five hydroxybenzoic acids (gallic, protocatechuic, 4-hydroxybenzoic, salicylic and vanillic acid), two hydroxycinnamic acids (chlorogenic and neochlorogenic acid), one dimerised polyphenol (ellagic acid) and five flavonoids (luteolin, rutin, quercetin-3-glucose and kaempferol). Five anthocyanins were also detected in the noni juice samples--cyanidin, cyanidin-3-glucose, malvidin-3-glucose, pelargonidin and delphinidin. Although there have been limited studies reporting individual anthocyanins from _M. citrifolia_ fruit, [32] did detect a moderate concentration of total anthocyanins (16 mg/100 g) in this species. Furthermore, many brands of noni juice are reported to include grape and blueberry juice, in addition to noni fruit juice [14]. Glycos of all four anthocyanin types detected here (cyanidin, malvidin, pelargonidin and delphinidin) have been reported from grapes or blueberries [33,34]. Consequently, this may be the source of some of these anthocyanins, rather than the noni fruit itself.