# Antibacterial and Antiproliferative Potential of Green, Roasted, and Spent Coffee Extracts
## 2 Results and Discussion  
### Extraction Yield, Total Phenolic Content, and Antiradical Scavenging Activity  
Coffee polyphenols and their antioxidant activity have been considered a potential source of new value-added bioactive compounds and, as such, have received increasing attention from the scientific and medical communities [13; 14]. As indicated in Table 1, the yield percentage of polyphenols in GB and RC (ethanolic and aqueous) extracts ranged from 17% to 23%, while that in SCG (ethanolic and aqueous) extracts ranged from 11% to 12%. The content of total phenolic (TPC) compounds in ethanolic extracts (of GB, RC, and SCG) had the greatest phenolic content (range 196-298 \(\upmu\)g CAE\(\cdot\)mg\({}^{-1}\)), while lower phenolic contents were found in aqueous extracts (of GB, RC, and SCG). Particularly, the ethanolic SCG extract exhibited the highest TPC content (298 \(\upmu\)g CAE\(\cdot\)mg\({}^{-1}\)), as well as presenting antiradical activity against ABTS\({}^{\bullet\star}\) and DPPH radicals, inhibiting the 50% of these radicals (IC\({}_{50}\)) at concentrations of 7.5 and 44.8 \(\upmu\)g\(\cdot\)mL\({}^{-1}\), respectively. The variation in extraction yield, TPC, and in ABTS\({}^{\bullet\star}\) and DPPH antiradical scavenging activity could be due to the type of coffee, solvent employed, and coffee processing. According to [PERSON] [15] and [PERSON] [16], the main compounds found in coffee beans (GB and RC) include esters and diesters \begin{table}
\begin{tabular}{c c c c c c} \hline \hline  & **Sample** & \begin{tabular}{c} **Yield** \\ **(\%)** \\ \end{tabular} & \begin{tabular}{c} **TPC** \\ **(\(\upmu\)g CAE\(\cdot\)mg\({}^{-1}\) Dry Extract)** \\ \end{tabular} & \
\begin{tabular}{c} **ABTS** \\ **(IC\({}_{50}\)\(\upmu\)g\(\cdot\)mL\({}^{-1}\))** \\ \end{tabular} &
\begin{tabular}{c} **DPPH** \\ **(IC\({}_{50}\)\(\upmu\)g\(\cdot\)mL\({}^{-1}\))** \\ \end{tabular} \\ \hline \multirow{4}{*}{Ethanolic} & GB & 19.28 \(\pm\) 0.21 b & 196.05 \(\pm\) 1.21 c & 10.76 \(\pm\) 0.14 bc & 87.60 \(\pm\) 1.68 ab \\  & RC & 17.57 \(\pm\) 0.10 c & 244.97 \(\pm\) 8.66 b & 13.21 \(\pm\) 3.60 b & 59.11 \(\pm\) 7.11 c \\  & SCG & 11.82 \(\pm\) 0.34 e & 298.33 \(\pm\) 1.41 a & 7.50 \(\pm\) 0.58 c & 44.88 \(\pm\) 5.81 c \\  & GB & 22.17 \(\pm\) 0.39 a & 160.57 \(\pm\) 1.82 e & 19.54 \(\pm\) 0.33 a & 96.79 \(\pm\) 5.12 a \\  & RC & 23.28 \(\pm\) 0.79 a & 188.00 \(\pm\) 3.10 d & 6.32 \(\pm\) 1.45 c & 79.55 \(\pm\) 8.70 b \\  & SCG & 12.80 \(\pm\) 0.42 d & 187.13 \(\pm\) 1.01 cd & 9.99 \(\pm\) 2.87 bc & 51.20 \(\pm\) 6.13 c \\ \hline \hline \end{tabular}
\end{table} 
Table 1: Total phenols and the antiradical scavenging activity of coffee extracts. of \(p\)-coumaric, caffe, and ferulic acids with quinic acids (caffeoylquinic acids, dicaffeoylquinic acids, feruloylquinic acids, and \(p\)-coumaroylquinic acids). These groups of compounds are collectively known as chlorogenic acids. It should be noted that, according to [PERSON] et al. [17], coffee roasting leads to a reduction in the contents of chlorogenic acids, in comparison with green coffee brews, ranging from 56% to 99% decrease after 6 or 15 min of processing time, respectively. In addition, these authors corroborated that chlorogenic acids are incorporated into melanoidins during the roasting process. [PERSON] et al. [18] reported TPC ranging from 6.33 to 28.26 mg gallic acid equivalent g\({}^{-1}\) dry SCG, as well as a total chlorogenic acid content total content ranging from 1.65 to 6.09 mg\(\cdot\)g\({}^{-1}\) dry SCG. The TPC content in ethanolic and aqueous extracts followed SCG > RC > GB. These differences can be attributed to the transformations that occur during coffee processing (e.g., releasing of bound phenolics during roasting and the subsequent drying and sonication prior to obtaining SCG samples). According to [PERSON] et al. [19] and [PERSON] et al.