Whatman no 1 filter paper

Seaweed extraction for HPLC analysis: A nanopowder of Turbinaria triquetra seaweed (1 g) was rinsed in 10 mL methanol 70% in glass bottles. Bottles were shaken for 24 h at room temperature in an orbital shaker (Heidolph—Unimax 2010-Germany). The extract was filtered through Whatman No. 1 filter paper; the residue was washed two times with an aliquot of methanol 70% and filtered through Whatman No. 1 filter paper. The net filtrate was adjusted to 10 mL with methanol 70%. HPLC analysis of the 70% methanol extract was carried out using HPLC (Agilent technologies, 1260 Infinity- Mundelein, IL, USA). A 4.6 mm × 250 mm i.d., 5 m, Eclipse C18 column was used for separation. Water (A) and 0.05% trifluoroacetic acid in acetonitrile (B) were the components of the mobile phase, which had a flow rate of 0.9 mL/min. The mobile phase was programmed consecutively in a linear gradient as follows: 0 min (82% A); 0–5 min (80% A); 5–8 min (60% A); 8–12 min (60% A); 12–15 min (82% A); 15–16 min (82% A); or 16–20 (82% A). The multi-wavelength detector was detected at 280 nm. Injection volume was 5 μL of the sample solutions and the column was kept at a constant temperature of 40 °C.

For the aqueous extract, the dried bark of Z. armatum was converted into a fine powder, of which 50 g was added to 300 mL of deionized water and kept at RT for 15 days. The resulting extract after filtering by Whatman No.1 filter paper was used for preparing the AgNPs. For the methanolic bark extract, 50 g of its powder was added to 300 mL of methanol and kept for 15 days at RT. The obtained extract, after filtering (Whatman No.1 filter paper) and drying by rotary evaporator under reduced pressure, was used for the experiments.

Fresh C. asiatica aerial parts was obtained locally and processed as previously reported.^{26 (link)} The plant sample was washed with tap water and rinsed with reverse osmosis water. The aerial parts were air-dried to reduce moisture content for 12 hour and further oven dried at 60 °C for another 12 hours. The dried sample was ground into fine powder and stored in an opaque bottle at −20 °C for further extraction.
Dried C. asiatica powder (50 g) was extracted using 500 mL of ethanol/water mixture (80 : 20 v/v) for 2 hours while gently stirring with an overhead stirrer. The mixture was filtered using a Buchner funnel overlaid with Whatman No 1 filter paper. The collected marc was re-extracted. The combined filtrate was concentrated using rotary evaporator at 40 °C to one-third of its original volume. Thereafter, the filtrate was kept at 4 °C overnight. A clear supernatant was obtained and subjected to reduced pressure in a speed-vac in order to remove any residual organic solvent. The mixture was filtered using Whatman No. 1 filter paper under gravity and then lyophilized to give a light brown powder (Fig. 1) hereafter referred to as C. asiatica phenolic extract (CAPE). CAPE was stored at −20 °C protected from light.