Almond

Arecatannin B1 is a B type proanthocyanidin found in the betel nut.^[1] It is an arecatannin trimer with a 4β→6 bond.

References

^ Screening of various plant extracts used in Ayurvedic medicine for inhibitory effects on human immunodeficiency virus type 1 (HIV-1) protease. Kusumoto I.T., Nakabayashi T., Kida H., Miyashiro H., Hattori M., Namba T. and Shimotohno K., PTR. Phytotherapy research, 1995, vol. 9, no3, pp. 180-184, INIST 3499215

Types of procyanidins
A-type proanthocyanidins	Dimers : Procyanidin A1 A2 Trimers:Cinnamtannin B1 Tetramers: Arecatannin A2
B type proanthocyanidins	Dimers : Procyanidin B1 B2 B3 B4 B5 B6 B8 D (ent-Epicatechin(4α→8)catechin) Trimers: Arecatannin B1 (epicatechin-(4β→8)-epicatechin-(4β→6)-catechin) Procyanidin C1 (epicatechin-(4β→8)-epicatechin-(4β→8)-epicatechin) Procyanidin C2 (catechin-(4α→8)-catechin-(4α→8)-catechin) Tetramers : Cinnamtannin A2
Types	Arecatannins Arecatannin A1 Arecatannin A3 Arecatannin B2 Arecatannin C1