Effect of crystallization of caffeic acid enhanced stability and dual biological efficacy

Figures & data

Figure 1. (A) The molecular structure of caffeic acid (CA) draw at 50% probability (B) shows the molecular packing.

Note: Crystal CCDC Depository CRM: 0001000261615, CCDC 1433127.

Figure 2. In vitro toxic effects of CA in the R28 cell lines (A, B) and U87 MG cells (C, D). The IC₅₀ of CA was 109.52 μg/ml (F) and 532.83 μg/ml (G) for R28 and U87 MG cells, respectively. The R28 cells were not affected and proliferated at lowest dose (6.25 μg/ml) of caffeic acid (E, H) in serum insult assay.

Note: The dose dependent effects of CA was plotted and IC₅₀ was determined using non-linear regression analysis.

Table 1. Crystal data and structure refinement parameters for CA

Compound	CA
Empirical formula	C9 H8 O4
Formula weight	180.15
Temperature (K)	294 K
Wavelength (Å)	0.71073
Crystal system	Monoclinic
Space group	P 21/n
Unit cell dimensions
a (Å)	6.7154(5)
b (Å)	5.7725(4)
c (Å)	21.1336(16)
α (°)	90
β (°)	93.9107(11)
γ (°)	90
Volume (Å^3)	817.33(10)
Z	4
Calculated density (Dx, g cm^−3)	1.464
Radiation type λ (Å)	M0 K/α
F(0 0 0)	376.0
Crystal size (mm) (h, k, l max)	9 × 8 × 31
Crystal color	Faint yellow
Scan range θ(°)(max)	31.622
Absorption coefficient (μ) (mm^−1)	0.117
Maximum and minimum transmission	0.986 and 0.950
Goodness-of-fit on F ^2	0.995
Data/restrains/parameters	2736/1.119/130
Final R indices [I > 2σ(I)]	R 1 = 0.0629, wR 2 = 0.1861

Figure 3. The molecular structure of CA labeled with: (A) bond angles, (B) bond lengths, and (C) torsion angles based on the crystallographic details.

Scheme 1. Isolation of caffeic acid (CA) from rosmarinic acid (RA).