Aug 10 (Reuters) - Manulife Financial Corp slightly beat analysts' estimates for second-quarter core profit but saw earnings drop from a year earlier, due to market volatility that weighed on its asset management unit and COVID-19 restrictions in Asia.

Canada's largest life insurer reported core earnings of C$1.56 billion ($1.2 billion), or 78 Canadian cents a share, in the three months ended June 30, compared with C$1.68 billion, or 83 Canadian cents a share, a year earlier. Analysts had expected 76 cents a share.

Analysts had forecast a muted second quarter for Canadian life insurers, on expectations that their substantial asset management units would take a hit from equity market declines. They also noted that lingering COVID-19 restrictions in Asia could prove a challenge, a headwind the company had flagged in its previous quarterly results announcement.

Manulife reported core earnings declines of 14% in its global wealth and asset management unit as fee income and assets under management declined; 4.6% in its U.S. business on lower demand for some insurance products due to higher inflation; and 2.5% in Asia, on lower sales, particularly in Hong Kong and Japan.

An 8.5% increase in its Canadian earnings, lifted by growth in new business value, helped offset the declines somewhat.

Net income attributable to shareholders was C$1.09 billion or 53 Canadian cents per share, compared with C$2.65 billion, or C$1.33 a share, a year earlier. ($1 = 1.2771 Canadian dollars) (Reporting by Nichola Saminather in Toronto; Additional reporting by Mehnaz Yasmin in Bengaluru; Editing by Aditya Soni and Stephen Coates)